FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
IMPELLER, MULTI-BLADE AIR-SENDING DEVICE, AND AIR-CONDITIONING
APPARATUS;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

2
DESCRIPTION
Title of Invention
IMPELLER, MULTI-BLADE AIR-SENDING DEVICE, AND AIR-CONDITIONING
APPARATUS
5
Technical Field
[0001]
The present disclosure relates to an impeller, a multi-blade air-sending device
including the impeller, and an air-conditioning apparatus including the multi-blade air10 sending device.
Background Art
[0002]
Hitherto, a multi-blade air-sending device has a volute scroll casing and an
impeller housed inside the scroll casing and configured to rotate around an axis (see,
15 for example, Patent Literature 1). The impeller of the multi-blade air-sending device
of Patent Literature 1 has a discoid backing plate, an annular rim, and blades
arranged radially. The blades of the impeller are configured such that main blades
and intermediate blades are alternately arranged and the inside diameters of the main
and intermediate blades increase from the backing plate toward the rim. Further,
20 each of the blades of the impeller is a sirocco blade (forward-swept blade) having a
blade outlet angle of larger than or equal to 100 degrees, includes an inducer portion
of a turbo blade (swept-back blade) as an inner circumferential portion of the blade,
and is configured such that the ratio of the blade inside diameter to the blade outside
diameter of the main blades beside the backing plate is lower than or equal to 0.7.
25 Citation List
Patent Literature
[0003]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2000-240590
30 Summary of Invention
3
Technical Problem
[0004]
However, the multi-blade air-sending device of Patent Literature 1 cannot
expect sufficient pressure recovery from the intermediate blades, as the ratio of an
5 outer circumferential sirocco blade and the ratio of an inner circumferential turbo
blade of each of the intermediate blades are about equal. Further, the multi-blade
air-sending device of Patent Literature 1 cannot expect sufficient pressure recovery
from the blades beside the rim, as the blades of the impeller are sirocco blades
beside the rim.
10 [0005]
The present disclosure is intended to solve the aforementioned problem, and
has as an object to provide an impeller capable of improving pressure recovery, a
multi-blade air-sending device including the impeller, and an air-conditioning
apparatus including the multi-blade air-sending device.
15 Solution to Problem
[0006]
An impeller according to an aspect of the present disclosure includes a backing
plate configured to be driven by rotating, an annular rim disposed so as to face the
backing plate, and a plurality of blades arranged in a circumferential direction around
20 a virtual rotation axis of the backing plate. One end of each of the plurality of blades
is connected with the backing plate, and the other end of each of the plurality of
blades is connected with the rim. Each of the plurality of blades has an inner
circumferential end located closer to the rotation axis in a radial direction around the
rotation axis, an outer circumferential end located closer to an outer circumference
25 than the inner circumferential end in the radial direction, a sirocco blade portion being
forward-swept and including the outer circumferential end and having a blade outlet
angle of larger than 90 degrees, and a turbo blade portion being swept-back and
including the inner circumferential end, a first region located closer to the backing
plate than a middle point in an axial direction of the rotation axis, and a second region
30 located closer to the rim than the first region. Each of the plurality of blades is
4
formed such that a blade length in the first region is longer than a blade length in the
second region. In the first region and the second region, a ratio of the turbo blade
portion in the radial direction is larger than a ratio of the sirocco blade portion in the
radial direction.
5 [0007]
A multi-blade air-sending device according to an aspect of the present
disclosure includes the impeller thus configured and a scroll casing housing the
impeller and having a peripheral wall formed into a volute shape and a side wall
having a bellmouth forming an air inlet communicating with a space formed by the
10 backing plate and the plurality of blades.
[0008]
An air-conditioning apparatus according to an aspect of the present disclosure
includes the multi-blade air-sending device thus configured.
Advantageous Effects of Invention
15 [0009]
According to an aspect of the present disclosure, in the first and second
regions of the impeller, the ratio of the turbo blade portion in the radial direction is
larger than the ratio of the sirocco blade portion in the radial direction. The impeller
and the multi-blade air-sending device have a high ratio of the turbo blade portion in
20 any region between the backing plate and the rim, can achieve sufficient pressure
recovery through the blades, and can better improve pressure recovery than an
impeller or a multi-blade air-sending device that does not include such a
configuration.
Brief Description of Drawings
25 [0010]
[Fig. 1] Fig. 1 is a perspective view schematically illustrating a multi-blade airsending device according to Embodiment 1.
[Fig. 2] Fig. 2 is an outside drawing schematically illustrating a configuration of
the multi-blade air-sending device according to Embodiment 1 as viewed from an
30 angle parallel with a rotation axis.
5
[Fig. 3] Fig. 3 is a schematic cross-sectional view of the multi-blade air-sending
device as taken along line A-A in Fig. 2.
[Fig. 4] Fig. 4 is a perspective view of an impeller of the multi-blade air-sending
device according to Embodiment 1.
5 [Fig. 5] Fig. 5] Fig. 5 is a side view of the impeller of Fig. 4.
[Fig. 6] Fig. 6 is a schematic view of blades in a cross-section of the impeller as
taken along line C-C in Fig. 5.
[Fig. 7] Fig. 7 is a schematic view of the blades in a cross-section of the
impeller as taken along line D-D in Fig. 5.
10 [Fig. 8] Fig. 8 is a schematic view illustrating a relationship between the
impeller and bellmouths in a cross-section of the multi-blade air-sending device as
taken along line A-A in Fig. 2.
[Fig. 9] Fig. 9 is a schematic view illustrating a relationship between blades and
a bellmouth as viewed from an angle parallel with the rotation axis in a second cross15 section of the impeller in Fig. 8.
[Fig. 10] Fig. 10 is a schematic view illustrating a relationship between the
impeller and the bellmouths in the cross-section of the multi-blade air-sending device
as taken along line A-A in Fig. 2.
[Fig. 11] Fig. 11 is a schematic view illustrating a relationship between the
20 blades and a bellmouth as viewed from an angle parallel with the rotation axis in the
impeller in Fig. 10.
[Fig. 12] Fig. 12 is a conceptual diagram explaining a relationship between the
impeller and a motor in the multi-blade air-sending device according to Embodiment
1.
25 [Fig. 13] Fig. 13 is a conceptual diagram of a multi-blade air-sending device
according to a first modification of the multi-blade air-sending device shown in Fig. 12.
[Fig. 14] Fig. 14 is a conceptual diagram of a multi-blade air-sending device
according to a second modification of the multi-blade air-sending device shown in Fig.
12.
30 [Fig. 15] Fig. 15 is a cross-sectional view schematically illustrating a multi-blade
6
air-sending device according to Embodiment 2.
[Fig. 16] Fig. 16 is a cross-sectional view schematically illustrating a multi-blade
air-sending device according to a comparative example.
[Fig. 17] Fig. 17 is a cross-sectional view schematically illustrating the workings
5 of the multi-blade air-sending device according to Embodiment 2.
[Fig. 18] Fig. 18 is a cross-sectional view of a multi-blade air-sending device
according to a first modification of the multi-blade air-sending device shown in Fig. 15.
[Fig. 19] Fig. 19 is a cross-sectional view of a multi-blade air-sending device
according to a second modification of the multi-blade air-sending device shown in Fig.
10 15.
[Fig. 20] Fig. 20 is a schematic view illustrating a relationship between a
bellmouth and a blade of a multi-blade air-sending device according to Embodiment
3.
[Fig. 21] Fig. 21 is a schematic view illustrating a relationship between a
15 bellmouth and a blade of a modification of the multi-blade air-sending device
according to Embodiment 3.
[Fig. 22] Fig. 22 is a cross-sectional view schematically illustrating a multi-blade
air-sending device according to Embodiment 4.
[Fig. 23] Fig. 23 is a schematic view of blades as viewed from an angle parallel
20 with a rotation axis in an impeller of Fig. 22.
[Fig. 24] Fig. 24 is a schematic view of the blades in a cross-section of the
impeller as taken along line D-D in Fig. 22.
[Fig. 25] Fig. 25 is a perspective view of an air-conditioning apparatus
according to Embodiment 5.
25 [Fig. 26] Fig. 26 is a diagram illustrating an internal configuration of the airconditioning apparatus according to Embodiment 5.
Description of Embodiments
[0011]
In the following, an impeller, a multi-blade air-sending device, and an air30 conditioning apparatus according to an embodiment are described, for example, with
7
reference to the drawings. In the following drawings including Fig. 1, relative
relationships in dimension between components, the shapes of the components, or
other features of the components may be different from actual ones. Further,
components given identical signs in the following drawings are identical or equivalent
5 to each other, and these signs are adhered to throughout the full text of the
description. Further, the directive terms (such as "upper", "lower", "right", "left",
"front", and "back") used as appropriate for ease of comprehension are merely so
written for convenience of explanation, and are not intended to limit the placement or
orientation of a device or a component.
10 [0012]
Embodiment 1
[Multi-blade Air-sending Device 100]
Fig. 1 is a perspective view schematically illustrating a multi-blade air-sending
device 100 according to Embodiment 1. Fig. 2 is an outside drawing schematically
15 illustrating a configuration of the multi-blade air-sending device 100 according to
Embodiment 1 as viewed from an angle parallel with a rotation axis RS. Fig. 3 is a
schematic cross-sectional view of the multi-blade air-sending device 100 as taken
along line A-A in Fig. 2. A basic structure of the multi-blade air-sending device 100 is
described with reference to Figs. 1 to 3. It should be noted that Figs. 1 to 3
20 schematically show an overall structure of the multi-blade air-sending device 100, and
a configuration of blades 12, which is a special feature of the multi-blade air-sending
device 100, is described in detail with reference to other drawings. The multi-blade
air-sending device 100 is a double-suction centrifugal air-sending device into which
air is suctioned through both ends in an axial direction of a virtual rotation axis RS of
25 an impeller 10. The multi-blade air-sending device 100 is a multi-blade centrifugal
air-sending device, and has an impeller 10 configured to generate a flow of gas and a
scroll casing 40 housing the impeller 10 inside.
[0013]
(Scroll Casing 40)
30 The scroll casing 40 houses the impeller 10 inside for use in the multi-blade air-
8
sending device 100, and rectifies a flow of air blown out from the impeller 10. The
scroll casing 40 has a scroll portion 41 and a discharge portion 42.
[0014]
(Scroll Portion 41)
5 The scroll portion 41 forms an air trunk through which a dynamic pressure of a
flow of gas generated by the impeller 10 is converted into a static pressure. The
scroll portion 41 has a side wall 44a covering the impeller 10 from an axial direction of
a rotation axis RS of a shaft portion 11b of the impeller 10 and having formed therein
an air inlet 45 through which air is taken in and a peripheral wall 44c surrounding the
10 impeller 10 from a radial direction of the rotation axis RS of the shaft portion 11b of
the impeller 10. Further, the scroll portion 41 has a tongue 43 located between the
discharge portion 42 and a scroll start portion 41a of the peripheral wall 44c to form a
curved surface and configured to guide the flow of gas generated by the impeller 10
toward a discharge port 42a via the scroll portion 41. The radial direction of the
15 rotation axis RS is a direction perpendicular to the axial direction of the rotation axis
RS. An internal space of the scroll portion 41 formed by the peripheral wall 44c and
the side wall 44a serves as a space in which the air blown out from the impeller 10
flows along the peripheral wall 44c.
[0015]
20 (Side Wall 44a)
The side wall 44a is disposed at both sides of the impeller 10 in the axial
direction of the rotation axis RS of the impeller 10. In the side wall 44a of the scroll
casing 40, the air inlet 45 is formed so that air can flow between the impeller 10 and
the outside of the scroll casing 40. The inlet port 45 is formed in a circular shape,
25 and is disposed so that the center of the air inlet 45 and the center of the shaft portion
11b of the impeller 10 substantially coincide with each other. It should be noted that
the shape of the air inlet 45 is not limited to the circular shape but may be another
shape such as an elliptical shape. The scroll casing 40 of the multi-blade airsending device 100 is a double-suction casing having side walls 44a at both sides of
30 the backing plate 11 in the axial direction of the rotation axis RS of the shaft portion
9
11b with air inlets 45 formed in the side walls 44a. The multi-blade air-sending
device 100 has two side walls 44a in the scroll casing 40. The two side walls 44a
are formed so as to face each other via the peripheral wall 44c. More specifically, as
shown in Fig. 3, the scroll casing 40 has a first side wall 44a1 and a second side wall
5 44a2 as the side walls 44a. The first side wall 44a1 forms a first air inlet 45a facing
a plate surface of the backing plate 11 on which the after-mentioned first rim 13a is
disposed. The second side wall 44a2 forms a second air inlet 45b facing a plate
surface of the backing plate 11 on which the after-mentioned second rim 13b is
disposed. It should be noted that the aforementioned air inlet 45 is a generic name
10 for the first air inlet 45a and the second air inlet 45b.
[0016]
The air inlet 45 provided in the side wall 44a is formed by a bellmouth 46.
That is, the bellmouth 46 forms an air inlet 45 communicating with a space formed by
the backing plate 11 and a plurality of blades 12. The bellmouth 46 rectifies a flow of
15 gas to be suctioned into the impeller 10 and causes the flow of gas to flow into an air
inlet 10e of the impeller 10. The bellmouth 46 has an opening having a diameter
gradually decreasing from the outside toward the inside of the scroll casing 40.
Such a configuration of the side wall 44a allows air near the air inlet 45 to smoothly
flow along the bellmouth 46 and efficiently flow into the impeller 10 through the air
20 inlet 45.
[0017]
(Peripheral Wall 44c)
The peripheral wall 44c guides the flow of gas generated by the impeller 10
toward the discharge port 42a along a curved wall surface. The peripheral wall 44a
25 is a wall provided between side walls 44a facing each other, and forms a curved
surface in a direction of rotation R of the impeller 10. The peripheral wall 44c is for
example disposed parallel with the axial direction of the rotation axis RS of the
impeller 10 to cover the impeller 10. It should be noted that the peripheral wall 44c
may be formed at a slant relative to the axial direction of the rotation axis RS of the
30 impeller 10, and is not limited to being formed to be disposed parallel with the axial
10
direction of the rotation axis RS. The peripheral wall 44c forms an inner
circumferential surface covering the impeller 10 from the radial direction of the shaft
portion 11b and facing the after-mentioned plurality of blades 12. The peripheral wall
44c faces a side of each of the blades 12 through which air is blown out from the
5 impeller 10. As shown in Fig. 2, the peripheral wall 44c is provided over an area
from the scroll start portion 41a, which is located at a boundary with the tongue 43, to
a scroll end portion 41b located at a boundary between the discharge portion 42 and
the scroll portion 41 at a side away from the tongue 43 along the direction of rotation
R of the impeller 10. The scroll start portion 41a is an end portion of the peripheral
10 wall 44c, which forms a curved surface, situated on an upstream side of a flow of gas
generated by rotation of the impeller 10, and the scroll end portion 41b is an end
portion of the peripheral wall 44c situated on a downstream side of the flow of gas
generated by rotation of the impeller 10.
[0018]
15 The peripheral wall 44c is formed in a volute shape. An example of the volute
shape is a volute shape based on a logarithmic spiral, a spiral of Archimedes, or an
involute curve. An inner peripheral surface of the peripheral wall 44c forms a curved
surface smoothly curved along a circumferential direction of the impeller 10 from the
scroll start portion 41a, at which the volute shape starts rolling, to the scroll end
20 portion 41b, at which the volute shape finishes rolling. Such a configuration allows
air sent out from the impeller 10 to smoothly flow through the space between the
impeller 10 and the peripheral wall 44c in a direction toward the discharge portion 42.
This effects an efficient rise in static pressure of air from the tongue 43 toward the
discharge portion 42 in the scroll casing 40.
25 [0019]
(Discharge Portion 42)
The discharge portion 42 forms a discharge port 42a through which a flow of
gas generated by the impeller 10 and having passed through the scroll portion 41 is
discharged. The discharge portion 42 is formed by a hollow pipe having a
30 rectangular cross-section orthogonal to a flow direction of air flowing along the
11
peripheral wall 44c. It should be noted that the cross-sectional shape of the
discharge portion 42 is not limited to a rectangle. The discharge portion 42 forms a
flow passage through which air sent out from the impeller 10 and flowing through a
gap between the peripheral wall 44c and the impeller 10 is guided to be exhausted
5 out of the scroll casing 40.
[0020]
As shown in Fig. 1, the discharge portion 42 is formed by an extension plate
42b, a diffuser plate 42c, a first side plate portion 42d, a second side plate portion
42e, or other components. The extension plate 42b is formed integrally with the
10 peripheral wall 44c so as to smoothly continue into the scroll end portion 41b
downstream of the peripheral wall 44c. The diffuser plate 42c is formed integrally
with the tongue 43 of the scroll casing 40 and faces the extension plate 42b. The
diffuser plate 42c is formed at a predetermined angle to the extension plate 42b so
that the cross-sectional area of the flow passage gradually increases along a flow
15 direction of air in the discharge portion 42. The first side plate portion 42d is formed
integrally with the first side wall 44a1 of the scroll casing 40, and the second side
plate portion 42e is formed integrally with the opposite second side wall 44a2 of the
scroll casing 40. Moreover, the first side plate portion 42d and the second side plate
portion 42e are formed between the extension plate 42b and the diffuser plate 42c.
20 Thus, the discharge portion 42 has a rectangular cross-section flow passage formed
by the extension plate 42b, the diffuser plate 42c, the first side plate portion 42d, and
the second side plate portion 42e.
[0021]
(Tongue 43)
25 In the scroll casing 40, the tongue 43 is formed between the diffuser plate 42c
of the discharge portion 42 and the scroll start portion 41a of the peripheral wall 44c.
The tongue 43 is formed with a predetermined radius of curvature, and the peripheral
wall 44c is smoothly connected with the diffuser plate 42c via the tongue 43. The
tongue 43 reduces inflow of air from the scroll start to the scroll end of a volute flow
30 passage. The tongue 43 is provided in an upstream part of a ventilation flue, and
12
has a role to effect diversion into a flow of air in the direction of rotation R of the
impeller 10 and a flow of air in a discharge direction from a downstream part of the
ventilation flue toward the discharge port 42a. Further, a flow of air flowing into the
discharge portion 42 rises in static pressure during passage through the scroll casing
5 40 to be higher in pressure than in the scroll casing 40. Therefore, the tongue 43
has a function of separating such different pressures.
[0022]
(Impeller 10)
The impeller 10 is a centrifugal fan. The impeller 10 is driven into rotation, for
10 example, by a motor (not illustrated). The rotation generates a centrifugal force with
which the impeller 10 forcibly sends out air outward in a radial direction. The
impeller 10 is rotated, for example, by the motor in a direction of rotation R indicated
by an arrow. As shown in Figs. 1 to 3, the impeller 10 has a backing plate 11 having
a disk shape, an annular rim 13, and several blades 12 arranged radially in a
15 circumferential direction of the backing plate 11 on a peripheral edge of the backing
plate 11.
[0023]
The backing plate 11 needs only be in the shape of a plate, and may, for
example, have a non-disk shape such as a polygonal shape. Further, the backing
20 plate 11 may be formed such that as shown in Fig. 3, the thickness of the backing
plate 11 increases toward the center in a radial direction around the rotation axis RS,
or may be formed such that the thickness is uniform in the radial direction around the
rotation axis RS. The backing plate 11 has provided in a central part thereof a shaft
portion 11b with which the motor (not illustrated) is connected. The backing plate 11
25 is driven into rotation by the motor via the shaft portion 11b.
[0024]
The plurality of blades 12 are arranged in a circumferential direction around a
virtual rotation axis RS of the backing plate 11. One end of each of the plurality of
blades 12 is connected with the backing plate 11, and the other end of each of the
30 plurality of blades 12 is connected with the rim 13. Each of the plurality of blades 12
13
is disposed between the backing plate 11 and the rim 13. The plurality of blades 12
are provided on both sides of the backing plate 11 in an axial direction of a rotation
axis RS of the shaft portion 11b. The blades 12 are placed at regular spacings from
each other on the peripheral edge of the backing plate 11. A configuration of the
5 blades 12 will be described in detail later.
[0025]
The annular rim 13 of the impeller 10 is attached to ends of the plurality of
blades 12 opposite to the backing plate 11 in the axial direction of the rotation axis RS
of the shaft portion 11b. The rim 13 is disposed in the impeller 10 so as to face the
10 backing plate 11. The rim 13 couples the plurality of blades 12 with each other,
thereby maintaining a positional relationship between the tip of each blade 12 and the
tip of the other blade 12 and reinforcing the plurality of blades 12.
[0026]
As shown in Fig. 3, the impeller 10 has the backing plate 11, a first blade
15 portion 112a, and a second blade portion 112b. The first blade portion 112a and the
second blade portion 112b are formed by the plurality of blades 12 and the rim 13.
More specifically, the first blade portion 112a is formed by an annular first rim 13a
disposed so as to face the backing plate 11 and a plurality of blades 12 disposed
between the backing plate 11 and the first rim 13a. The second blade portion 112b
20 is formed by an annular second blade portion 13b disposed on a side of the backing
plate 11 opposite to the first rim 13a so as to face the backing plate 11 and a plurality
of blades 12 disposed between the backing plate 11 and the second rim 13b. It
should be noted that the rim 13 is a generic name for the first rim 13a and the second
rim 13b, and the impeller 10 has the first rim 13a on one side of the backing plate 11
25 in the axial direction of the rotation axis RS, and has the second rim 13b on the other
side.
[0027]
The first blade portion 112a is disposed on one plate surface of the backing
plate 11, and the second blade portion 112b is disposed on the other plate surface of
30 the backing plate 11. That is, the plurality of blades 12 are provided on both sides of
14
the backing plate 11 in the axial direction of the rotation axis RS, and the first blade
portion 112a and the second blade portion 112b are provided back to back with each
other via the backing plate 11. In Fig. 3, the first blade portion 112a is disposed on
the left side of the backing plate 11, and the second blade portion 112b is disposed on
5 the right side of the backing plate 11. However, the first blade portion 112a and the
second blade portion 112b need only be provided back to back with each other via
the backing plate 11. The first blade portion 112a may be disposed on the right side
of the backing plate 11, and the second blade portion 112b may be disposed on the
left side of the backing plate 11. In the following description, those blades 12 which
10 form the first blade portion 112a and those blades 12 which form the second blade
portion 112b are collectively referred to as "blades 12" unless otherwise noted.
[0028]
The impeller 10 is formed in a tubular shape by the plurality of blades 12
disposed on the backing plate 11. Moreover, the impeller 10 has an air inlet 10e
15 formed at a side of the rim 13 opposite to the backing plate 11 in the axial direction of
the rotation axis RS of the shaft portion 11b and configured to cause gas to flow into a
space surrounded by the backing plate 11 and the plurality of blades 12. The
impeller 10 has its blades 12 and rims 13 disposed on both plate surfaces,
respectively, of the backing plate 11, and has its air inlets 10e formed at both plate
20 surfaces, respectively, of the backing plate 11.
[0029]
The impeller 10 is driven into rotation around the rotation axis RS by driving of
the motor (not illustrated). The rotation of the impeller 10 causes gas outside the
multi-blade air-sending device 100 to be suctioned into the space surrounded by the
25 backing plate 11 and the plurality of blades 12 through the air inlet 45 formed in the
scroll casing 40 and the air inlet 10e of the impeller 10. Moreover, the rotation of the
impeller 10 causes air suctioned into the space surrounded by the backing plate 11
and the plurality of blades 12 to be sent out outward in a radial direction of the
impeller 10 through a space between a blade 12 and an adjacent blade 12.
30 [0030]
15
[Configuration of Blades 12 in Detail]
Fig. 4 is a perspective view of the impeller 10 of the multi-blade air-sending
device 100 according to Embodiment 1. Fig. 5 is a side view of the impeller 10 of
Fig. 4. Fig. 6 is a schematic view of the blades 12 in a cross-section of the impeller
5 10 as taken along line C-C in Fig. 5. Fig. 7 is a schematic view of the blades 12 in a
cross-section of the impeller 10 as taken along line D-D in Fig. 5. In Fig. 5, a middle
point MP of the impeller 10 indicates a middle point in the axial direction of the
rotation axis RS in the plurality of blades 12 forming the first blade portion 112a.
Moreover, in the plurality of blades 12 forming the first blade portion 112a, a region
10 from the middle point MP in the axial direction of the rotation axis RS to the backing
plate 11 is a backing-plate-side blade region 122a serving as a first region of the
impeller 10. Further, in the plurality of blades 12 forming the first blade portion 112a,
a region from the middle point MP in the axial direction of the rotation axis RS to an
end portion of the rim 13 is a rim-side blade region 122b serving as a second region
15 of the impeller 10. That is, each of the plurality of blades 12 has a first region
located closer to the backing plate 11 than the middle point MP in the axial direction of
the rotation axis RS and a second region located closer to the rim 13 than the first
region. As shown in Fig. 6, the cross-section taken along line C-C in Fig. 5 is a
cross-section of the plurality of blades 12 beside the backing plate 11 of the impeller
20 10, that is, in the backing-plate-side blade region 122a serving as the first region.
This cross-section of the blades 12 beside the backing plate 11 is a first cross-section
of the impeller 10 made by cutting through a portion of the impeller 10 close to the
backing plate 11 along a first plane 71 perpendicular to the rotation axis RS. Note
here that the portion of the impeller 10 close to the backing plate 11 is, for example, a
25 portion of the impeller 10 closer to the backing plate 11 than a middle point of the
backing-plate-side blade region 122a in the axial direction of the rotation axis RS or a
portion of the impeller 10 in which end portions of the blades 12 facing the backing
plate 11 are located in the axial direction of the rotation axis RS. As shown in Fig. 7,
the cross-section taken along line D-D in Fig. 5 is a cross-section of the plurality of
30 blades 12 beside the rim 13 of the impeller 10, that is, in the rim-side blade region
16
122b serving as the second region. This cross-section of the blades 12 beside the
rim 13 is a second cross-section of the impeller 10 made by cutting through a portion
of the impeller 10 close to the backing plate 11 along a second plane 72
perpendicular to the rotation axis RS. Note here that the portion of the impeller 10
5 close to the rim 13 is, for example, a portion of the impeller 10 closer to the rim 13
than a middle point of the rim-side blade region 122b in the axial direction of the
rotation axis RS or a portion of the impeller 10 in which end portions of the blades 12
facing the rim 13 are located in the axial direction of the rotation axis RS.
[0031]
10 A configuration of the blades 12 in the second blade portion 112b is similar to a
configuration of the blades 12 in the first blade portion 112a. That is, in Fig. 5, a
middle point MP of the impeller 10 indicates a middle point in the axial direction of the
rotation axis RS in the plurality of blades 12 forming the second blade portion 112b.
Moreover, in the plurality of blades 12 forming the second blade portion 112b, a
15 region from the middle point MP in the axial direction of the rotation axis RS to the
backing plate 11 is a backing-plate-side blade region 122a serving as a first region of
the impeller 10. Further, in the plurality of blades 12 forming the second blade
portion 112b, a region from the middle point MP in the axial direction of the rotation
axis RS to an end portion of the second rim 13b is a rim-side blade region 122b
20 serving as a second region of the impeller 10. Although the foregoing description
assumes that a configuration of the first blade portion 112a and a configuration of the
second blade portion are the same, a configuration of the impeller 10 is not limited to
such a configuration but may be a configuration in which the first blade portion 112a
and the second blade portion 112b are different from each other. That is, both or
25 either the first blade portion 112a and/or the second blade portion 112b may have the
configuration of the blades 12 to be described below. The following describes the
configuration of the blades 12 in detail with reference to Figs. 4 to 7.
[0032]
As shown in Figs. 4 to 7, the plurality of blades 12 include a plurality of first
30 blades 12A and a plurality of second blades 12B. The plurality of blades 12 includes
17
an alternate arrangement of a first blade 12A and or more second blades 12B in the
circumferential direction of the impeller 10. As shown in Figs. 4 and 6, the impeller
10 has two second blades 12B disposed between a first blade 12A and a first blade
12A disposed adjacent to the first blade 12A in the direction of rotation R. Note,
5 however, that the number of second blades 12B that are disposed between a first
blade 12A and a first blade 12A disposed adjacent to the first blade 12A in the
direction of rotation R is not limited to 2 but may be 1 or larger than or equal to 3.
That is, at least one of the plurality of second blades 12B is disposed between two of
the plurality of first blades 12A adjacent to each other in the circumferential direction.
10 [0033]
As shown in Fig. 6, in the first cross-section of the impeller 10 as taken along
the first plane 71 perpendicular to the rotation axis RS, each of the first blades 12A
has an inner circumferential end 14A located closer to the rotation axis RS in a radial
direction around the rotation axis RS and an outer circumferential end 15A located
15 closer to an outer circumference than the inner circumferential end 14A in the radial
direction. In each of the plurality of first blades 12A, the inner circumferential end
14A is disposed in front of the outer circumferential end 15A in the direction of rotation
R of the impeller 10. As shown in Fig. 4, the inner circumferential end 14A serves as
a leading edge 14A1 of the first blade 12A, and the outer circumferential end 15A
20 serves as a trailing edge 15A1 of the first blade 12A. As shown in Fig. 6, the
impeller 10 has fourteen first blades 12A disposed therein. However, the number of
first blades 12A is not limited to 14 but may be smaller or larger than 14.
[0034]
As shown in Fig. 6, in the first cross-section of the impeller 10 as taken along
25 the first plane 71 perpendicular to the rotation axis RS, each of the second blades
12B has an inner circumferential end 14B located closer to the rotation axis RS in a
radial direction around the rotation axis RS and an outer circumferential end 15B
located closer to an outer circumference than the inner circumferential end 14B in the
radial direction. In each of the plurality of second blades 12B, the inner
30 circumferential end 14B is disposed in front of the outer circumferential end 15B in the
18
direction of rotation R of the impeller 10. As shown in Fig. 4, the inner
circumferential end 14B serves as a leading edge 14B1 of the second blade 12B, and
the outer circumferential end 15B serves as a trailing edge 15B1 of the second blade
12B. As shown in Fig. 6, the impeller 10 has twenty-eight second blades 12B
5 disposed therein. However, the number of second blades 12B is not limited to 28
but may be smaller or larger than 28.
[0035]
The following describes a relationship between the first blades 12A and the
second blades 12B. As shown in Figs. 4 and 7, the blade length of each of portions
10 of each of the first blades 12A closer to the first rim 13a and the second rim 13b than
the middle points MP in a direction along the rotation axis RS is equal to the blade
length of each of portions of each of the second blades 12B closer to the first rim 13a
and the second rim 13b than the middle points MP in the direction along the rotation
axis RS. Meanwhile, as shown in Figs. 4 and 6, the blade length of a portion each of
15 the first blades 12A closer to the backing plate 11 than the middle point MP in the
direction along the rotation axis RS is greater than the blade length of a portion of
each of the second blades 12B closer to the backing plate 11 than the middle point
MP in the direction along the rotation axis RS, and increases toward the backing plate
11. Thus, in the present embodiment, the blade length of at least a portion of each
20 of the first blades 12A in the direction along the rotation axis RS is greater than the
blade length of at least a portion of each of the second blades 12B in the direction
along the rotation axis RS. It should be noted that the term "blade length" here
means the length of each of the first blades 12A in the radial direction of the impeller
10 and the length of each of the second blades 12B in the radial direction of the
25 impeller 10.
[0036]
As shown in Fig. 6, in the first cross-section closer to the backing plate 11 than
the middle point MP shown in Fig. 5, the diameter of a circle C1 passing through the
inner circumferential ends 14a of the plurality of first blades 12A around the rotation
30 axis RS, that is, the inside diameter of the first blades 12A, is assumed to be an
19
inside diameter ID1. The diameter of a circle C3 passing through the outer
circumferential ends 15A of the plurality of first blades 12A around the rotation axis
RS, that is, the outside diameter of the first blades 12A, is assumed to be an outside
diameter OD1. One-half of the difference between the outside diameter OD1 and
5 the inside diameter ID1 is equal to the blade length L1a of each of the first blades 12A
in the first cross-section (Blade Length L1a = (Outside Diameter OD1 - Inside
Diameter ID1)/2). Note here that the ratio of the inside diameter to the outside
diameter of the first blades 12A is lower than or equal to 0.7. That is, the plurality of
first blades 12A are configured such that the ratio of the inside diameter ID1 formed
10 by the inner circumferential end 14A of each of the plurality of first blades 12A and to
the outside diameter OD1 formed by the outer circumferential end 15A of each of the
plurality of first blades 12A is lower than or equal to 0.7. It should be noted that in a
common multi-blade air-sending device, the blade length of a blade in a cross-section
perpendicular to a rotation axis is shorter than the width dimension of a blade in a
15 direction parallel with the rotation axis. In the present embodiment, too, the
maximum blade length of each of the first blades 12A, that is, the blade length of an
end portion of each of the first blades 12A close to the backing plate 11, is shorter
than the width dimension W (see Fig. 5) of each of the first blades 12A in the direction
parallel with the rotation axis.
20 [0037]
Further, in the first cross-section, the diameter of a circle C2 passing through
the inner circumferential ends 14B of the plurality of second blades 12B around the
rotation axis RS, that is, the inside diameter of the second blades 12B, is assumed to
be an inside diameter ID2 that is larger than the inside diameter ID1 (Inside Diameter
25 ID2 > Inside Diameter ID1). The diameter of the circle C3 passing through the outer
circumferential ends 15B of the plurality of second blades 12B around the rotation
axis RS, that is, the outside diameter of the second blades 12B, is assumed to be an
outside diameter OD2 that is equal to the outside diameter OD1 (Outside Diameter
OD2 = Outside Diameter OD1). One-half of the difference between the outside
30 diameter OD2 and the inside diameter ID2 is equal to the blade length L2a of each of
20
the second blades 12B in the first cross-section (Blade Length L2a = (Outside
Diameter OD2 - Inside Diameter ID2)/2). The blade length L2a of each of the
second blades 12B in the first cross-section is shorter than the blade length L1a of
each of the first blades 12A in the same cross-section (Blade Length L2a < Blade
5 Length L1a). Note here that the ratio of the inside diameter to the outside diameter
of the second blades 12B is lower than or equal to 0.7. That is, the plurality of
second blades 12B are configured such that the ratio of the inside diameter ID2
formed by the inner circumferential end 14B of each of the plurality of second blades
12B to the outside diameter OD2 formed by the outer circumferential end 15B of each
10 of the plurality of second blades 12B is lower than or equal to 0.7.
[0038]
Meanwhile, as shown in Fig. 7, in the second cross-section closer to the rim 13
than the middle point MP shown in Fig. 5, the diameter of a circle C7 passing through
the inner circumferential ends 14A of the first blades 12A around the rotation axis RS
15 is assumed to be an inside diameter ID3. The inside diameter ID3 is larger than the
inside diameter ID1 of the first cross-section (Inside Diameter ID3 > Inside Diameter
ID1). The diameter of a circle C8 passing through the outer circumferential ends
15A of the first blades 12A around the rotation axis RS is assumed to be an outside
diameter OD3. One-half of the difference between the outside diameter OD3 and
20 the inside diameter ID1 is equal to the blade length L1b of each of the first blades 12A
in the second cross-section (Blade Length L1b = (Outside Diameter OD3 - Inside
Diameter ID3)/2).
[0039]
Further, let it be assumed that in the second cross-section, the diameter of the
25 circle C7 passing through the inner circumferential ends 14B of the second blades
12B around the rotation axis RS is an inside diameter ID4. The inside diameter ID4
is equal to the inside diameter ID3 in the same cross-section (Inside Diameter ID4 =
Inside Diameter ID3). The diameter of the circle C8 passing through the outer
circumferential ends 15B of the second blades 12B around the rotation axis RS is
30 assumed to be an outside diameter OD4. The outside diameter OD4 is equal to the
21
outside diameter OD3 in the same cross-section (Outside Diameter OD4 = Outside
Diameter OD3). One-half of the difference between the outside diameter OD4 and
the inside diameter ID4 is equal to the blade length L2b of each of the second blades
12B in the second cross-section (Blade Length L2b = (Outside Diameter OD4 - Inside
5 Diameter ID4)/2). The blade length L2b of each of the second blades 12B in the
second cross-section is equal to the blade length L1b of each of the first blades 12A
in the same cross-section (Blade Length L2b = Blade Length L1b).
[0040]
When viewed from an angle parallel with the rotation axis RS, the first blades
10 12A in the second cross-section shown in Fig. 7 overlap the first blades 12A in the
first cross-section shown in Fig. 6 so as not to extend off the contours of the first
blades 12A. For this reason, the impeller 10 satisfies the relationships "Outside
Diameter OD3 = Outside Diameter OD1", "Inside Diameter ID3  Inside Diameter
ID1", and "Blade Length L1b  Blade Length L1a".
15 [0041]
Similarly, when viewed from an angle parallel with the rotation axis RS, the
second blades 12B in the second cross-section shown in Fig. 7 overlap the second
blades 12B in the first cross-section shown in Fig. 6 so as not to extend off the
contours of the second blades 12B. For this reason, the impeller 10 satisfies the
20 relationships "Outside Diameter OD4 = Outside Diameter OD2", "Inside Diameter ID4
 Inside Diameter ID2", and "Blade Length L2b  Blade Length L2a".
[0042]
Note here that as mentioned above, the ratio of the inside diameter ID1 to the
outside diameter OD1 of the first blades 12A is lower than or equal to 0.7. Since the
25 blades 12 are configured such that Inside Diameter ID3  Inside Diameter ID1, Inside
Diameter ID4  Inside Diameter ID2, and Inside Diameter ID2 > Inside Diameter ID1,
the inside diameter of the first blades 12A can be the blade inside diameter of the
blades 12. Further, since the blades 12 are configured such that Outside Diameter
OD3 = Outside Diameter OD1, Outside Diameter OD4 = Outside Diameter OD2, and
30 Outside Diameter OD2 = Outside Diameter OD1, the outside diameter of the first
22
blades 12A can be the blade outside diameter of the blades 12. Moreover, in a case
in which the blades 12 forming the impeller 10 are seen as a whole, the blades 12 are
configured such that the ratio of the blade inside diameter to the blade outside
diameter of the blades 12 is lower than or equal to 0.7. It should be noted that the
5 blade inside diameter of the plurality of blades 12 is formed by the inner
circumferential end of each of the plurality of blades 12. That is, the blade inside
diameter of the plurality of blades 12 is formed by the leading edges 14A1 of the
plurality of blades 12. Further, the blade outside diameter of the plurality of blades
12 is formed by the outer circumferential end of each of the plurality of blade 12.
10 That is, the blade outside diameter of the plurality of blades 12 is formed by the
trailing edges 15A1 and 15B1 of the plurality of blades 12.
[0043]
[Configuration of First Blades 12A and Second Blades 12B]
In a comparison between the first cross-section shown in Fig. 6 and the second
15 cross-section shown in Fig. 7, each of the first blades 12A has the relationship "Blade
Length L1a > Blade Length L1b". That is, each of the plurality of blades 12 is formed
such that a blade length in the first region is longer than a blade length in the second
region. More specifically, each of the first blades 12A is formed such that its blade
length decreases from the backing plate 11 toward the rim 13 in the axial direction of
20 the rotation axis RS. Similarly, in a comparison between the first cross-section
shown in Fig. 6 and the second cross-section shown in Fig. 7, each of the second
blades 12B has the relationship "Blade Length L2a > Blade Length L2b". That is,
each of the second blades 12B is formed such that the blade length decreases from
the backing plate 11 toward the rim 13 in the axial direction of the rotation axis RS.
25 Moreover, as shown in Fig. 3, the first blades 12A and the second blades 12B are
inclined such that the blade inside diameter increases from the backing plate 11
toward the rim 13. That is, the plurality of blades 12 form an inclined portion 141A
inclined such that the inner circumferential ends 14A forming the leading edges 14A1
extend away from the rotation axis RS so that the blade inside diameter increases
30 from the backing plate 11 toward the rim 13. Similarly, the plurality of blades 12 form
23
an inclined portion 141B inclined such that the inner circumferential ends 14B forming
the leading edges 14B1 extend away from the rotation axis RS so that the blade
inside diameter increases from the backing plate 11 toward the rim 13.
[0044]
5 As shown in Figs. 6 and 7, each of the first blades 12A has a first sirocco blade
portion 12A1 being forward-swept and a first turbo blade portion 12A2 being sweptback. In the radial direction of the impeller 10, the first sirocco blade portion 12A1
forms an outer circumference of the first blade 12A, and the first turbo blade portion
12A2 forms an inner circumference of the first blade 12A. That is, each of the first
10 blades 12A is configured such that the first turbo blade portion 12A2 and the first
sirocco blade portion 12A1 are arranged in this order from the rotation axis RS toward
the outer circumference in the radial direction of the impeller 10. In each of the first
blades 12A, the first turbo blade portion 12A2 and the first sirocco blade portion 12A1
are integrally formed. The first turbo blade portion 12A2 forms the leading edge
15 14A1 of the first blade 12A, and the first sirocco blade portion 12A1 forms the trailing
edge 15A1 of the first blade 12A. In the radial direction of the impeller 10, the first
turbo blade portion 12A2 linearly extends from the inner circumferential end 14A
forming the leading edge 14A1 toward the outer circumference.
[0045]
20 In the radial direction of the impeller 10, a region forming the first sirocco blade
portion 12A1 of each of the first blades 12A is defined as a first sirocco region 12A11,
and a region forming the first turbo blade portion 12A2 of each of the first blades 12A
is defined as a first turbo region 12A21. Each of the first blades 12A is configured
such that the first turbo region 12A21 is larger than the first sirocco region 12A11 in
25 the radial direction of the impeller 10. Moreover, in both the backing-plate-side blade
region 122a serving as the first region and the rim-side blade region 122b serving as
the second region, the impeller 10 has the relationship "First Sirocco Region 12A11 <
First Turbo Region 12A21" in the radial direction of the impeller 10. That is, the
impeller 10 and each of the first blades 12A are configured such that in both the
30 backing-plate-side blade region 122a serving as the first region and the rim-side
24
blade region 122b serving as the second region, a ratio of the first turbo blade portion
12A2 is larger than a ratio of the first sirocco blade portion 12A1 in the radial direction
of the impeller 10.
[0046]
5 Similarly, as shown in Figs. 6 and 7, each of the second blades 12B has a
second sirocco blade portion 12B1 being forward-swept and a second turbo blade
portion 12B2 being swept-back. In the radial direction of the impeller 10, the second
sirocco blade portion 12B1 forms an outer circumference of the second blade 12B,
and the second turbo blade portion 12B2 forms an inner circumference of the second
10 blade 12B. That is, each of the second blades 12B is configured such that the
second turbo blade portion 12B2 and the second sirocco blade portion 12B1 are
arranged in this order from the rotation axis RS toward the outer circumference in the
radial direction of the impeller 10. In each of the second blades 12B, the second
turbo blade portion 12B2 and the second sirocco blade portion 12B1 are integrally
15 formed. The second turbo blade portion 12B2 forms the leading edge 14B1 of the
second blade 12B, and the first sirocco blade portion 12B1 forms the trailing edge
15B1 of the second blade 12B. In the radial direction of the impeller 10, the second
turbo blade portion 12B2 linearly extends from the inner circumferential end 14B
forming the leading edge 14B1 toward the outer circumference.
20 [0047]
In the radial direction of the impeller 10, a region forming the second sirocco
blade portion 12B1 of each of the second blades 12B is defined as a second sirocco
region 12B11, and a region forming the second turbo blade portion 12B2 of each of
the second blades 12B is defined as a second turbo region 12B21. Each of the
25 second blades 12B is configured such that the second turbo region 12B21 is larger
than the second sirocco region 12B11 in the radial direction of the impeller 10.
Moreover, in both the backing-plate-side blade region 122a serving as the first region
and the rim-side blade region 122b serving as the second region, the impeller 10 has
the relationship "Second Sirocco Region 12B11 < Second Turbo Region 12B21" in
30 the radial direction of the impeller 10. That is, the impeller 10 and each of the
25
second blades 12B are configured such that in both the backing-plate-side blade
region 122a serving as the first region and the rim-side blade region 122b serving as
the second region, a ratio of the second turbo blade portion 12B2 is larger than a ratio
of the second sirocco blade portion 12B1 in the radial direction of the impeller 10.
5 [0048]
According to the foregoing configuration, the plurality of blades 12 are
configured such that in both the backing-plate-side blade region 122a and the rimside blade region 122b, a region of a turbo blade portion is larger than a region of a
sirocco blade portion in the radial direction of the impeller 10. That is, the plurality of
10 blades 12 are configured such that in both the backing-plate-side blade region 122a
and the rim-side blade region 122b, a ratio of the turbo blade portion is larger than a
ratio of the sirocco blade portion in the radial direction of the impeller 10, and have
the relationship "Sirocco Region < Turbo Region". In other words, each of the
plurality of blades 12 is configured such that in the first region and the second region,
15 a ratio of the turbo blade portion in the radial direction is larger than a ratio of the
sirocco blade portion in the radial direction.
[0049]
As shown in Fig. 6, a blade outlet angle of the first sirocco blade portion 12A1
of each of the first blades 12A in the first cross-section is assumed to be a blade
20 outlet angle 1. The blade outlet angle 1 is defined as an angle formed by a
tangent line TL1 and a center line CL1 of the first sirocco blade portion 12A1 at the
outer circumferential end 15A at an intersection of a segment of the circle C3 around
the rotation axis RS and the outer circumferential end 15A. This blade outlet angle
1 is an angle of larger than 90 degrees. A blade outlet angle of the second sirocco
25 blade portion 12B1 of each of the second blades 12B in the same cross-section is
assumed to be a blade outlet angle 2. The blade outlet angle 2 is defined as an
angle formed by a tangent line TL2 and a center line CL2 of the second sirocco blade
portion 12B1 at the outer circumferential end 15B at an intersection of a segment of
the circle C3 around the rotation axis RS and the outer circumferential end 15B. The
30 blade outlet angle 2 is an angle of larger than 90 degrees. The blade outlet angle
26
2 of the second sirocco blade portion 12B1 is equal to the blade outlet angle 1 of
the first sirocco blade portion 12A1 (Blade Outlet Angle 2 = Blade Outlet Angle 1).
The first sirocco blade portion 12A1 and the second sirocco blade portion 12B1 are
formed in arcs to curve out in a direction opposite to the direction of rotation R when
5 viewed from an angle parallel with the rotation axis RS.
[0050]
As shown in Fig. 7, the impeller 10 is configured such that in the second crosssection, too, the blade outlet angle 1 of the first sirocco blade portion 12A1 and the
blade outlet angle 2 of the second sirocco blade portion 12B1 are equal to each
10 other. That is, each of the plurality of blades 12 has a sirocco blade portion being
forward-swept and extending from the backing plate 11 to the rim 13 and having a
blade outlet angle of larger than 90 degrees.
[0051]
Further, as shown in Fig. 6, a blade outlet angle of the first turbo blade portion
15 12A2 of each of the first blades 12A in the first cross-section is assumed to be a blade
outlet angle 1. The blade outlet angle 1 is defined as an angle formed by a
tangent line TL3 and a center line CL3 of the first turbo blade portion 12A2 at an
intersection of a segment of a circle C4 around the rotation axis RS and the first turbo
blade portion 12A2. This blade outlet angle 1 is an angle of smaller than 90
20 degrees. A blade outlet angle of the second turbo blade portion 12B2 of each of the
second blades 12B in the same cross-section is assumed to be a blade outlet angle
2. The blade outlet angle 2 is defined as an angle formed by a tangent line TL4
and a center line CL4 of the second turbo blade portion 12B2 at an intersection of a
segment of the circle C4 around the rotation axis RS and the second turbo blade
25 portion 12B2. The blade outlet angle 2 is an angle of smaller than 90 degrees.
The blade outlet angle 2 of the second turbo blade portion 12B2 is equal to the
blade outlet angle 1 of the first turbo blade portion 12A2 (Blade Outlet Angle 2 =
Blade Outlet Angle 1).
[0052]
30 Although not illustrated in Fig. 7, the impeller 10 is configured such that in the
27
second cross-section, too, the blade outlet angle 1 of the first turbo blade portion
12A2 and the blade outlet angle 2 of the second turbo blade portion 12B2 are equal
to each other. Further, the blade outlet angle 1 and the blade outlet angle 2 are
angles of smaller than 90 degrees.
5 [0053]
As shown in Figs. 6 and 7, each of the first blades 12A has a first radial blade
portion 12A3 serving as a portion of connection between the first turbo blade portion
12A2 and the first sirocco blade portion 12A1. The first radial blade portion 12A3 is
a portion configured to be a radial blade linearly extending in the radial direction of the
10 impeller 10. Similarly, each of the second blades 12B has a second radial blade
portion 12B3 serving as a portion of connection between the second turbo blade
portion 12B2 and the second sirocco blade portion 12B1. The second radial blade
portion 12B3 is a portion configured to be a radial blade linearly extending in the
radial direction of the impeller 10. The first radial blade portion 12A3 and the second
15 radial blade portion 12B3 each have a blade angle of 90 degrees. More specifically,
an angle formed by a tangent line at an intersection of a center line of the first radial
blade portion 12A3 and a circle C5 around the rotation axis RS and the center line of
the first radial blade portion 12A3 is 90 degrees. Further, an angle formed by a
tangent line at an intersection of a center line of the second radial blade portion 12B3
20 and the circle C5 around the rotation axis RS and the center line of the second radial
blade portion 12B3 is 90 degrees.
[0054]
When a spacing between two of the plurality of blades 12 adjacent to each
other in the circumferential direction is defined as a blade spacing, the blade spacing
25 between a plurality of blades 12 widens from the leading edges 14A1 toward the
trailing edges 15A1 as shown in Figs. 6 and 7. Similarly, the blade spacing between
a plurality of blades 12 widens from the leading edges 14B1 toward the trailing edges
15B1. Specifically, a blade spacing in the turbo blade portion formed by the first
turbo blade portion 12A2 and the second turbo blade portion 12B2 widens from the
30 inner circumference toward the outer circumference. Moreover, a blade spacing in a
28
sirocco blade portion formed by a first sirocco blade portion 12A1 and a second
sirocco blade portion 12B1 is wider than the blade spacing in the turbo blade portion
and widens from the inner circumference toward the outer circumference. That is, a
blade spacing between a first turbo blade portion 12A2 and a second turbo blade
5 portion 12B2 or a blade spacing between adjacent second turbo blade portions 12B2
widens from the inner circumference toward the outer circumference. Further, a
blade spacing between a first sirocco blade portion 12A1 and a second sirocco blade
portion 12B1 or a blade spacing between adjacent second sirocco blade portions
12B1 is wider than the blade spacing in the turbo blade portion and widens from the
10 inner circumference toward the outer circumference.
[0055]
[Relationship between Impeller 10 and Scroll Casing 40]
Fig. 8 is a schematic view illustrating a relationship between the impeller 10
and bellmouths 46 in a cross-section of the multi-blade air-sending device 100 as
15 taken along line A-A in Fig. 2. Fig. 9 is a schematic view illustrating a relationship
between blades 12 and a bellmouth 46 as viewed from an angle parallel with the
rotation axis RS in a second cross-section of the impeller 10 in Fig. 8. As shown in
Figs. 8 and 9, a blade outside diameter OD formed by the outer circumferential end of
each of the plurality of blades 12 is larger than the inside diameter BI of a bellmouth
20 46 forming the scroll casing 40. It should be noted that the blade outside diameter
OD of the plurality of blades 12 is equal to the outside diameters OD1 and OD2 of the
first blades 12A and the outside diameter OD3 and OD4 of the second blades 12B
(Blade Outside Diameter OD = Outside Diameter OD1 = Outside Diameter OD2 =
Outside Diameter OD3 = Outside Diameter OD4).
25 [0056]
The impeller 10 is configured such that the first turbo region 12A21 is larger
than the first sirocco region 12A11 in the radial direction relative to the rotation axis
RS. That is, the impeller 10 and each of the first blades 12A are configured such
that the ratio of the first turbo blade portion 12A2 is larger than the ratio of the first
30 sirocco blade portion 12A1 in the radial direction relative to the rotation axis RS, and
29
have the relationship "First Sirocco Blade Portion 12A1 < First Turbo Blade Portion
12A2". The relationship between the ratio of the first sirocco blade portion 12A1 and
the ratio of the first turbo blade portion 12A2 in the radial direction of the rotation axis
RS holds in both the backing-plate-side blade region 122a serving as the first region
5 and the rim-side blade region 122b serving as the second region.
[0057]
Furthermore, a region of portions of the plurality of blades 12 situated closer to
the outer circumference than the inside diameter BI of the bellmouth 46 in the radial
direction relative to the rotation axis RS when viewed from an angle parallel with the
10 rotation axis RS is defined as an outer circumferential region 12R. It is desirable that
the impeller 10 be configured such that in the outer circumferential region 12R, too,
the ratio of the first turbo blade portion 12A2 is larger than the ratio of the first sirocco
blade portion 12A1. That is, in the outer circumferential region 12R of the impeller
10 situated closer to the outer circumference than the inside diameter BI of the
15 bellmouth 46 when viewed from an angle parallel with the rotation axis RS, a first
turbo region 12A21a is larger than the first sirocco region 12A11 in the radial direction
relative to the rotation axis RS. The first turbo region 12A21a is a region of the first
turbo region 12A21 situated closer to the outer circumference than the inside
diameter BI of the bellmouth 46 when viewed from an angle parallel with the rotation
20 axis RS. Moreover, in a case in which a first turbo blade portion 12A2 forming the
first turbo region 12A21a is a first turbo blade portion 12A2a, it is desirable that the
outer circumferential region 12R of the impeller 10 be configured such that a ratio of
the first turbo blade portion 12A2a is larger than the ratio of the first sirocco blade
portion 12A1. The relationship between the ratio of the first sirocco blade portion
25 12A1 and the ratio of the first turbo blade portion 12A2a in the outer circumferential
region 12R holds in both the backing-plate-side blade region 122a serving as the first
region and the rim-side blade region 122b serving as the second region.
[0058]
Similarly, the impeller 10 is configured such that the second turbo region 12B21
30 is larger than the second sirocco region 12B11 in the radial direction relative to the
30
rotation axis RS. That is, the impeller 10 and each of the second blades 12B are
configured such that the ratio of the second turbo blade portion 12B2 is larger than
the ratio of the second sirocco blade portion 12B1 in the radial direction relative to the
rotation axis RS, and have the relationship "Second Sirocco Blade Portion 12B1 <
5 Second Turbo Blade Portion 12B2". The relationship between the ratio of the
second sirocco blade portion 12B1 and the ratio of the second turbo blade portion
12B2 in the radial direction of the rotation axis RS holds in both the backing-plate-side
blade region 122a serving as the first region and the rim-side blade region 122b
serving as the second region.
10 [0059]
Furthermore, it is desirable that the impeller 10 be configured such that in the
outer circumferential region 12R, too, the ratio of the second turbo blade portion 12B2
is larger than the ratio of the second sirocco blade portion 12B1. That is, in the outer
circumferential region 12R of the impeller 10 situated closer to the outer
15 circumference than the inside diameter BI of the bellmouth 46 when viewed from an
angle parallel with the rotation axis RS, a second turbo region 12B21a is larger than
the second sirocco region 12B11 in the radial direction relative to the rotation axis RS.
The second turbo region 12B21a is a region of the second turbo region 12B21
situated closer to the outer circumference than the inside diameter BI of the bellmouth
20 46 when viewed from an angle parallel with the rotation axis RS. Moreover, in a
case in which a second turbo blade portion 12B2 forming the second turbo region
12B21a is a second turbo blade portion 12B2a, it is desirable that the outer
circumferential region 12R of the impeller 10 be configured such that a ratio of the
second turbo blade portion 12B2a is larger than the ratio of the second sirocco blade
25 portion 12B1. The relationship between the ratio of the second sirocco blade portion
12B1 and the ratio of the second turbo blade portion 12B2a in the outer
circumferential region 12R holds in both the backing-plate-side blade region 122a
serving as the first region and the rim-side blade region 122b serving as the second
region.
30 [0060]
31
Fig. 10 is a schematic view illustrating a relationship between the impeller 10
and the bellmouths 46 in the cross-section of the multi-blade air-sending device 100
as taken along line A-A in Fig. 2. Fig. 11 is a schematic view illustrating a
relationship between the blades 12 and a bellmouth 46 as viewed from an angle in
5 parallel with the rotation axis RS in the impeller 10 in Fig. 10. In Fig. 10, the outline
arrow L indicates a direction from which the impeller 10 is viewed parallel with the
rotation axis RS. As shown in Figs. 10 and 11, a circle passing through the inner
circumferential ends 14A of the plurality of first blades 12A around the rotation axis
RS at connecting locations between the first blades 12A and the backing plate 11
10 when viewed from an angle parallel with the rotation axis RS is defined as a circle
C1a. Moreover, the diameter of the circle C1a, that is, the inside diameter of the first
blades 12A at the connecting locations between the first blades 12A and the backing
plate 11, is assumed to be an inside diameter ID1a. Further, a circle passing through
the inner circumferential ends 14B of the plurality of second blades 12B around the
15 rotation axis RS at connecting locations between the second blades 12B and the
backing plate 11 when viewed from an angle parallel with the rotation axis RS is
defined as a circle C2a. Moreover, the diameter of the circle C2a, that is, the inside
diameter of the second blades 12B at the connecting locations between the second
blades 12B and the backing plate 11, is assumed to be an inside diameter ID2a.
20 The inside diameter ID2a is larger than the inside diameter ID1a (Inside Diameter
ID2a > Inside Diameter ID1a). Further, the diameter of a circle C3a passing through
the outer circumferential ends 15A of the plurality of first blades 12A and the outer
circumferential ends 15B of the plurality of second blades 12B around the rotation
axis RS when viewed from an angle parallel with the rotation axis RS, that is, the
25 outside diameter of the plurality of blades 12, is assumed to be a blade outside
diameter OD. Further, a circle passing through the inner circumferential ends 14A of
the plurality of first blades 12A around the rotation axis RS at connecting locations
between the first blades 12A and the rim 13 when viewed from an angle parallel with
the rotation axis RS is defined as a circle C7a. Moreover, the diameter of the circle
30 C7a, that is, the inside diameter of the first blades 12A at the connecting locations
32
between the first blades 12A and the rim 13, is assumed to be an inside diameter
ID3a. Further, a circle passing through the inner circumferential ends 14B of the
plurality of second blades 12B around the rotation axis RS at connecting locations
between the second blades 12B and the rim 13 when viewed from an angle parallel
5 with the rotation axis RS is the circle C7a. Moreover, the diameter of the circle C7a,
that is, the inside diameter of the second blades 12B at the connecting locations
between the second blades 12B and the rim 13, is assumed to be an inside diameter
ID4a.
[0061]
10 As shown in Figs. 10 and 11, the inside diameter BI of the bellmouth 46 is
located in a region of the first turbo blade portions 12A2 and the second turbo blade
portions 12B2 between the inside diameter ID1a of the first blades 12A beside the
backing plate 11 and the inside diameter ID3a of the first blades 12A beside the rim
13. More specifically, the inside diameter BI of the bellmouth 46 is larger than the
15 inside diameter ID1a of the first blades 12A beside the backing plate 11 and smaller
than the inside diameter ID3a of the first blades 12A beside the rim 13. That is, the
inside diameter BI of the bellmouth 46 is formed to be larger than the blade inside
diameter of the plurality of blades 12 beside the backing plate 11 and smaller than the
blade inside diameter of the plurality of blades 12 beside the rim 13. In other words,
20 an opening 46a forming the inside diameter BI of the bellmouth 46 is located in a
region of the first turbo blade portions 12A2 and the second turbo blade portions
12B2 between the circle C1a and the circle C7a when viewed from an angle parallel
with the rotation axis RS.
[0062]
25 Further, as shown in Figs. 10 and 11, the inside diameter BI of the bellmouth 46
is located in a region of the first turbo blade portions 12A2 and the second turbo blade
portions 12B2 between the inside diameter ID2a of the second blades 12B beside the
backing plate 11 and the inside diameter ID4a of the second blades 12B beside the
rim 13. More specifically, the inside diameter BI of the bellmouth 46 is larger than
30 the inside diameter ID2a of the second blades 12B beside the backing plate 11 and
33
smaller than the inside diameter ID4a of the second blades 12B beside the rim 13.
That is, the inside diameter BI of the bellmouth 46 is formed to be larger than the
blade inside diameter of the plurality of blades 12 beside the backing plate 11 and
smaller than the blade inside diameter of the plurality of blades 12 beside the rim 13.
5 More specifically, the inside diameter BI of the bellmouth 46 is formed to be larger
than a blade inside diameter formed by the inner circumferential end of each of the
plurality of blades 12 in the first region and smaller than a blade inside diameter
formed by the inner circumferential end of each of the plurality of blades 12 in the
second region. In other words, the opening 46a forming the inside diameter BI of the
10 bellmouth 46 is located in a region of the first turbo blade portions 12A2 and the
second turbo blade portions 12B2 between the circle C2a and the circle C7a when
viewed from an angle parallel with the rotation axis RS.
[0063]
Let it be assumed that as shown in Figs. 10 and 11, in the radial direction of the
15 impeller 10, a radial length of each of the first and second sirocco blade portions
12A1 and 12B1 is a distance SL. Further, in the multi-blade air-sending device 100,
the shortest distance between the plurality of blades 12 of the impeller 10 and the
peripheral wall 44c of the scroll casing 40 is assumed to be a distance MS. In this
case, the multi-blade air-sending device 100 is configured such that the distance MS
20 is more than twice as long as the distance SL (Distance MS > Distance SL  2).
Although the distance MS is shown in the A-A section of the multi-blade air-sending
device 100 in Fig. 10, the distance MS is the shortest distance from the peripheral
wall 44c of the scroll casing 40 and is not necessarily shown on the A-A section.
[0064]
25 Fig. 12 is a conceptual diagram explaining a relationship between the impeller
10 and a motor 50 in the multi-blade air-sending device 100 according to Embodiment
1. In Fig. 12, the dotted lines FL indicate a flow of air flowing from outside into the
scroll casing 40. As shown in Fig. 12, the multi-blade air-sending device 100 may
have, in addition to the impeller 10 and the scroll casing 40, a motor 50 configured to
30 rotate the backing plate 11 of the impeller 10. That is, the multi-blade air-sending
34
device 100 may have an impeller 10, a scroll casing 40 housing the impeller 10, and a
motor 50 configured to drive the impeller 10.
[0065]
The motor 50 is disposed adjacent to the side wall 44a of the scroll casing 40.
5 The motor 50 has a motor shaft 51 extending on the rotation axis RS of the impeller
10 and being inserted in the scroll casing 40 through a side surface of the scroll
casing 40.
[0066]
The backing plate 11 is disposed so as to be perpendicular to the rotation axis
10 RS along the side wall 44a of the scroll casing 40 facing the motor 50. The backing
plate 11 has provided in a central part thereof a shaft portion 11b with which the motor
shaft 51 is connected, and the motor shaft 51 is fixed to the shaft portion 11b of the
backing plate 11 while being inserted in the scroll casing 40. The motor shaft 51 of
the motor 50 is connected with the backing plate 11 of the impeller 10 to be fixed.
15 [0067]
Once the motor 50 is brought into operation, the plurality of blades 12 rotate
around the rotation axis RS via the motor shaft 51 and the backing plate 11. This
causes outside air to be suctioned into the impeller 10 through the air inlet 45 and
blown out into the scroll casing 40 by a booster action of the impeller 10. The air
20 blown out into the scroll casing 40 recovers its static pressure by having its speed
reduced in an expanded air trunk formed by the peripheral wall 44c of the scroll
casing 40, and is blown out to the outside through the discharge port 42a shown in
Fig. 1.
[0068]
25 As shown in Fig. 12, an outer peripheral wall 52 forming the outside diameter
MO1 of an end portion 50a of the motor 50 is located between a virtual extended
surface VF1 formed by extending the blade inside diameter of the blades 12 beside
the backing plate 11 in the axial direction of the rotation axis RS and a virtual
extended surface VF3 formed by extending the blade inside diameter of the blades 12
30 beside the rim 13 in the axial direction of the rotation axis RS. Further, the outer
35
peripheral wall 52 forming the outside diameter MO1 of the end portion 50a of the
motor 50 is disposed in such a location as to face the first turbo blade portions 12A2
and the second turbo blade portions 12B2 in the axial direction of the rotation axis
RS. More specifically, the outside diameter MO1 of the end portion 50a of the motor
5 50 is larger than the inside diameter ID1 of the plurality of first blades 12A beside the
backing plate 11 and smaller than the inside diameter ID3 of the plurality of first
blades 12A beside the rim 13. That is, the outside diameter MO1 of the end portion
50a of the motor 50 is formed to be larger than the blade inside diameter of the
plurality of blades 12 beside the backing plate 11 and smaller than the blade inside
10 diameter of the plurality of blades 12 beside the rim 13. Further, the outer peripheral
wall 52 at the end portion 50a of the motor 50 is located in a region of the first turbo
blade portions 12A2 and the second turbo blade portions 12B2 between the
aforementioned circles C1a and C7a when viewed from an angle parallel with the
rotation axis RS. In the multi-blade air-sending device 100, as for a dimension of the
15 outside diameter MO2 of a portion of the motor 50 other than the end portion 50a, a
size of the outside diameter MO2 is not limited.
[0069]
Fig. 13 is a conceptual diagram of a multi-blade air-sending device 100A
according to a first modification of the multi-blade air-sending device 100 shown in
20 Fig. 12. The multi-blade air-sending device 100A is configured such that an outer
peripheral wall 52 forming the outside diameter MO of a motor 50A is located
between a virtual extended surface VF1 formed by extending the blade inside
diameter of the blades 12 beside the backing plate 11 in the axial direction of the
rotation axis RS and a virtual extended surface VF3 formed by extending the blade
25 inside diameter of the blades 12 beside the rim 13 in the axial direction of the rotation
axis RS. Further, the outer peripheral wall 52 forming the outside diameter MO of
the motor 50A is disposed in such a location as to face the first turbo blade portions
12A2 and the second turbo blade portions 12B2 in the axial direction of the rotation
axis RS. More specifically, the outside diameter MO of the motor 50A is larger than
30 the inside diameter ID1 of the plurality of first blades 12A beside the backing plate 11
36
and smaller than the inside diameter ID3 of the plurality of first blades 12A beside the
rim 13. That is, the outside diameter MO of the motor 50A is formed to be larger
than the blade inside diameter of the plurality of blades 12 beside the backing plate
11 and smaller than the blade inside diameter of the plurality of blades 12 beside the
5 rim 13. Further, the outer peripheral wall 52 forming the outside diameter MO of the
motor 50A is located in a region of the first turbo blade portions 12A2 and the second
turbo blade portions 12B2 between the aforementioned circles C1a and C7a when
viewed from an angle parallel with the rotation axis RS.
[0070]
10 Fig. 14 is a conceptual diagram of a multi-blade air-sending device 100B
according to a second modification of the multi-blade air-sending device 100 shown in
Fig. 12. As shown in Fig. 14, an outer peripheral wall 52a forming the outside
diameter MO1a of an end portion 50a of a motor 50B is located between the rotation
axis RS and a virtual extended surface VF1 formed by extending the blade inside
15 diameter of the blades 12 beside the backing plate 11 in the axial direction of the
rotation axis RS. Further, the outer peripheral wall 52a forming the outside diameter
MO1a of the end portion 50a of the motor 50B is disposed in such a location as to
face the first turbo blade portions 12A2 and the second turbo blade portions 12B2 in
the axial direction of the rotation axis RS. More specifically, the outside diameter
20 MO1a of the end portion 50a of the motor 50B is smaller than the inside diameter ID1
of the plurality of first blades 12A beside the backing plate 11. That is, the outside
diameter MO1a of the end portion 50a of the motor 50B is formed to be smaller than
the blade inside diameter of the plurality of blades 12 beside the backing plate 11.
Further, the outer peripheral wall 52a at the end portion 50a of the motor 50B is
25 located within the aforementioned circle C1a when viewed from an angle parallel with
the rotation axis RS.
[0071]
Further, the multi-blade air-sending device 100B is configured such that an
outer peripheral wall 52b forming the outermost diameter MO2a of the motor 50B is
30 located between the virtual extended surface VF1 formed by extending the blade
37
inside diameter of the blades 12 beside the backing plate 11 in the axial direction of
the rotation axis RS and a virtual extended surface VF3 formed by extending the
blade inside diameter of the blades 12 beside the rim 13 in the axial direction of the
rotation axis RS. Further, the outer peripheral wall 52b forming the outermost
5 diameter MO2a of the motor 50B is disposed in such a location as to face the first
turbo blade portions 12A2 and the second turbo blade portions 12B2 in the axial
direction of the rotation axis RS. More specifically, the outermost diameter MO2a of
the motor 50B is larger than the inside diameter ID1 of the plurality of first blades 12A
beside the backing plate 11 and smaller than the inside diameter ID3 of the plurality of
10 first blades 12A beside the rim 13. That is, the outermost diameter MO2a of the
motor 50B is formed to be larger than the blade inside diameter of the plurality of
blades 12 beside the backing plate 11 and smaller than the blade inside diameter of
the plurality of blades 12 beside the rim 13. Further, the outer peripheral wall 52b
forming the outermost diameter MO2a of the motor 50B is located in a region of the
15 first turbo blade portions 12A2 and the second turbo blade portions 12B2 between the
aforementioned circles C1a and C7a when viewed from an angle parallel with the
rotation axis RS.
[0072]
[Working Effects of Impeller 10 and Multi-blade Air-sending Device 100]
20 The impeller 10 and the multi-blade air-sending device 100 are configured such
that in the first and second regions of the impeller 10, a ratio of the turbo blade portion
in the radial direction is larger than a ratio of the sirocco blade portion in the radial
direction. Since the impeller 10 and the multi-blade air-sending device 100 are
configured such that the ratio of the turbo blade portion is high in any region between
25 the backing plate 11 and the rim 13, sufficient pressure recovery can be achieved
through the plurality of blades 12. Therefore, the impeller 10 and the multi-blade airsending device 100 can better improve pressure recovery than an impeller or a multiblade air-sending device that does not include such a configuration. As a result, the
impeller 10 can improve the efficiency of the multi-blade air-sending device 100.
30 Furthermore, by including the foregoing configuration, the impeller 10 can reduce
38
leading edge separation of a flow of gas beside the rim 13.
[0073]
Further, each of the plurality of blades 12 has a radial blade portion serving a
portion of connection between the turbo blade portion and the sirocco blade portion
5 and having a blade angle of 90 degrees. By having the radial blade portion between
the turbo blade portion and the sirocco blade portion, the impeller 10 is free of an
abrupt angle change in the portion of connection between the sirocco blade portion
and the turbo blade portion. Therefore, the impeller 10 can reduce pressure
fluctuations in the scroll casing 40, increase the fan efficiency of the multi-blade air10 sending device 100, and further reduce noise.
[0074]
Further, the plurality of blades 12 are configured such that at least one of the
plurality of second blades 12B is disposed between two of the plurality of first blades
12A adjacent to each other in the circumferential direction. Since the impeller 10
15 and the multi-blade air-sending device 100 are configured such that in each of the
second blades 12B, too, the ratio of the turbo blade portion is high in any region
between the backing plate 11 and the rim 13, sufficient pressure recovery can be
achieved through the second blades 12B. Therefore, the impeller 10 and the multiblade air-sending device 100 can better improve pressure recovery than an impeller
20 or a multi-blade air-sending device that does not include such a configuration. As a
result, the impeller 10 can improve the efficiency of the multi-blade air-sending device
100. Furthermore, by including the foregoing configuration, the impeller 10 can
reduce leading edge separation of a flow of gas beside the rim 13.
[0075]
25 Further, the plurality of second blades 12B are formed such that a ratio of an
inside diameter formed by the inner circumferential end 14B of each of the plurality of
second blades 12B to an outside diameter formed by the outer circumferential end
15B of each of the plurality of second blades 12B is lower than or equal to 0.7.
Since the impeller 10 and the multi-blade air-sending device 100 are configured such
30 that in each of the second blades 12B, too, the ratio of the turbo blade portion is high
39
in any region between the backing plate 11 and the rim 13, sufficient pressure
recovery can be achieved through the second blades 12B. Therefore, the impeller
10 and the multi-blade air-sending device 100 can better improve pressure recovery
than an impeller or a multi-blade air-sending device that does not include such a
5 configuration. As a result, the impeller 10 can improve the efficiency of the multiblade air-sending device 100. Furthermore, by including the foregoing configuration,
the impeller 10 can reduce leading edge separation of a flow of gas beside the rim 13.
[0076]
Further, the plurality of blades 12 are configured such that in a portion of the
10 plurality of blades 12 situated closer to the outside than the inside diameter BI of the
bellmouth 46 in the radial direction relative to the rotation axis RS, a ratio of a region
of the turbo blade portion in the radial direction of the backing plate 11 is larger than a
ratio of a region of the sirocco blade portion in the radial direction of the backing plate
11. The plurality of blades 12 is configured such that such a configuration holds in
15 any region between the backing plate 11 and the rim 13. By including such a
configuration, the plurality of blades 12 can increase the amount of air that is
suctioned in a portion of the blades 12 inside the inside diameter BI of the bellmouth
46. Further, by increasing the ratio of the turbo blade portion in the portion of the
plurality of blades 12 situated closer to the outside than the inside diameter BI of the
20 bellmouth 46, the plurality of blades 12 can increase the volume of air that is emitted
from the impeller 10. Furthermore, by having such a configuration, the plurality of
blades 12 can increase pressure recovery in the scroll casing 40 of the multi-blade
air-sending device 100 and improve fan efficiency.
[0077]
25 Further, the inside diameter BI of the bellmouth 46 is formed to be larger than
the blade inside diameter of the plurality of blades 12 beside the backing plate 11 and
smaller than the blade inside diameter of the plurality of blades 12 beside the rim 13.
Therefore, the multi-blade air-sending device 100 can reduce interference between a
flow of suctioned gas flowing in through the air inlet 45 of the bellmouth 46 and the
30 blades 12 beside the rim 13 and further reduce noise.
40
[0078]
Further, the inside diameter BI of the bellmouth 46 is formed to be larger than
the blade inside diameter of the plurality of second blades 12B beside the backing
plate 11 and smaller than the blade inside diameter of the plurality of second blades
5 12B beside the rim 13. Therefore, the multi-blade air-sending device 100 can
reduce interference between a flow of suctioned gas flowing in through the air inlet 45
of the bellmouth 46 and the second blades 12B beside the rim 13 and further reduce
noise.
[0079]
10 Further, the distance MS, which is the shortest distance between the plurality of
blades 12 and the peripheral wall 44c, is more than twice as long as the radial length
of the sirocco blade portion. Therefore, the multi-blade air-sending device 100 can
achieve pressure recovery through the turbo blade portion, increase the distance
between the scroll casing 40 and the impeller 10 in a place where they are closest to
15 each other, and can therefore reduce noise.
[0080]
Further, the multi-blade air-sending device 100 is formed such that the outside
diameter MO1 of an end portion 50a of the motor 50 is larger than the blade inside
diameter of the plurality of blades 12 beside the backing plate 11 and smaller than the
20 blade inside diameter of the plurality of blades 12 beside the rim 13. By including
such a configuration, the multi-blade air-sending device 100 causes a flow of gas
from the vicinity of the motor 50 to be diverted into the axial direction of the rotation
axis RS of the impeller 10 and causes air to be smoothly flow into the scroll casing
40, thereby making it possible to increase the volume of air that is emitted from the
25 impeller 10. Furthermore, by having such a configuration, the multi-blade airsending device 100 can increase pressure recovery in the scroll casing 40 and
improve fan efficiency.
[0081]
Further, the multi-blade air-sending device 100A is formed such that the outside
30 diameter MO of the motor 50A is larger than the blade inside diameter of the plurality
41
of blades 12 beside the backing plate 11 and smaller than the blade inside diameter
of the plurality of blades 12 beside the rim 13. By including such a configuration, the
multi-blade air-sending device 100A causes a flow of gas from the vicinity of the
motor 50A to be diverted into the axial direction of the rotation axis RS of the impeller
5 10 and causes air to be smoothly flow into the scroll casing 40, thereby making it
possible to increase the volume of air that is emitted from the impeller 10.
Furthermore, by having such a configuration, the multi-blade air-sending device 100A
can increase pressure recovery in the scroll casing 40 and improve fan efficiency.
[0082]
10 Further, the multi-blade air-sending device 100B is formed such that the
outside diameter MO2a of the motor 50B is larger than the blade inside diameter of
the plurality of blades 12 beside the backing plate 11 and smaller than the blade
inside diameter of the plurality of blades 12 beside the rim 13 and the outside
diameter MO1a of an end portion 50a of the motor 50B is formed to be smaller than
15 the blade inside diameter of the plurality of blades 12 beside the backing plate 11.
By including such a configuration, the multi-blade air-sending device 100B can better
cause air to be smoothly flow into the scroll casing 40 and increase the volume of air
that is emitted from the impeller 10 than the multi-blade air-sending device 100A or
other devices. Furthermore, by having such a configuration, the multi-blade air20 sending device 100B can better increase pressure recovery in the scroll casing 40
and improve fan efficiency than the multi-blade air-sending device 100A or other
devices.
[0083]
Embodiment 2
25 [Multi-blade Air-sending Device 100C]
Fig. 15 is a cross-sectional view schematically illustrating a multi-blade airsending device 100C according to Embodiment 2. Fig. 16 is a cross-sectional view
schematically illustrating a multi-blade air-sending device 100H according to a
comparative example. Fig. 17 is a cross-sectional view schematically illustrating the
30 workings of the multi-blade air-sending device 100C according to Embodiment 2.
42
Fig. 15 is a cross-sectional view schematically illustrating effects of the multi-blade
air-sending device 100C according to Embodiment 2. The multi-blade air-sending
device 100C according to Embodiment 2 is described with reference to Figs. 15 to 17.
It should be noted that components having identical configurations as those of the
5 multi-blade air-sending device 100 or other devices of Figs. 1 to 14 are given identical
signs and a description of such components is omitted. An impeller 10C of the multiblade air-sending device 100C according to Embodiment 2 is intended to further
specify the configuration of the inclined portions 141A and 141B of the plurality of
blades 12 of the impeller 10 of the multi-blade air-sending device 100 according to
10 Embodiment 1. Accordingly, in the following description, the impeller 10C is
described with reference to Figs. 15 to 17 with a focus on a configuration of the
inclined portions 141A and 141B of the multi-blade air-sending device 100C according
to Embodiment 2.
[0084]
15 As mentioned above, the plurality of blades 12 form an inclined portion 141A
inclined such that the leading edges 14A1 extend away from the rotation axis RS so
that the blade inside diameter increases from the backing plate 11 toward the rim 13.
That is, the plurality of blades 12 form an inclined portion 141A inclined such that the
inner circumferential ends 14A extend away from the rotation axis RS so that the
20 blade inside diameter increases from the backing plate 11 toward the rim 13.
Similarly, the plurality of blades 12 form an inclined portion 141B inclined such that
the leading edges 14B1 extend away from the rotation axis RS so that the blade
inside diameter increases from the backing plate 11 toward the rim 13. That is, the
plurality of blades 12 form an inclined portion 141B inclined such that the inner
25 circumferential ends 14B extend away from the rotation axis RS so that the blade
inside diameter increases from the backing plate 11 toward the rim 13. The plurality
of blades 12 have gradients formed on the inner circumference by the inclined portion
141A and the inclined portion 141B.
[0085]
30 The inclined portion 141A is inclined relative to the rotation axis RS. The
43
inclined portion 141A has an angle of inclination preferably larger than 0 degree and
smaller than or equal to 60 degrees or more preferably larger than 0 degree and
smaller than or equal to 45 degrees. That is, an angle of inclination 1 between the
inclined portion 141A and the rotation axis RS is configured to preferably satisfy the
5 relationship "0 degree < 1  60 degrees" or more preferably satisfy the relationship
"0 degree < 1  45 degrees". In Fig. 15, the virtual line VL1 is a virtual line parallel
with the rotation axis RS. Therefore, an angle between the inclined portion 141A
and the virtual line VL1 is equal to the angle between the inclined portion 141A and
the rotation axis RS.
10 [0086]
Similarly, the inclined portion 141B is inclined relative to the rotation axis RS.
The inclined portion 141B has an angle of inclination preferably larger than 0 degree
and smaller than or equal to 60 degrees or more preferably larger than 0 degree and
smaller than or equal to 45 degrees. That is, an angle of inclination 2 between the
15 inclined portion 141B and the rotation axis RS is configured to preferably satisfy the
relationship "0 degree < 2  60 degrees" or more preferably satisfy the relationship
"0 degree < 2  45 degrees". In Fig. 15, the virtual line VL2 is a virtual line parallel
with the rotation axis RS. Therefore, an angle between the inclined portion 141B
and the virtual line VL2 is equal to the angle between the inclined portion 141B and
20 the rotation axis RS. The angle of inclination 1 and the angle of inclination 2 may
be the same as or different from each other.
[0087]
The blade height WH shown in Fig. 15 is less than or equal to 200 mm. The
blade height WH is the distance between the backing plate 11 and end portions 12t of
25 the plurality of blades 12 in the axial direction of the rotation axis RS, and is the
maximum distance between the backing plate 11 and the end portions 12t of the
plurality of blades 12 in the axial direction of the rotation axis RS. The blade height
WH is not limited to being less than or equal to 200 mm but may be greater than 200
mm.
30 [0088]
44
[Working Effects of Impeller 10C and Multi-blade Air-sending Device 100C]
As shown in Fig. 16, the multi-blade air-sending device 100H according to the
comparative example is configured such that an inside diameter IDh formed by the
leading edges 14H has a certain size in the axial direction of the rotation axis RS.
5 That is, the multi-blade air-sending device 100H according to the comparative
example does not have an inclined portion 141A or an inclined portion 141B, and
therefore does not have a gradient formed in the blade inside diameter. Therefore,
as shown in Fig. 16, the multi-blade air-sending device 100H according to the
comparative example is configured such that air (dotted line FL) to be suctioned into
10 the multi-blade air-sending device 100H easily passes through an end portion 12t of
the impeller 10H or a corner portion formed by the end portion 12t and a leading edge
14H. The end portion 12t of the impeller 10H or the corner portion formed by the
end portion 12t and the leading edge 14H is a portion of the blade 12 that is small in
area. Therefore, the air passes through a narrow gap between the blade 12 and an
15 adjacent blade 12, so that the multi-blade air-sending device 100H suctions the air
with high ventilation resistance.
[0089]
On the other hand, as shown in Fig. 17, the multi-blade air-sending device
100C has an inclined portion 141A and an inclined portion 141B at the leading edges
20 of the blades 12, and has a gradient formed in the blade inside diameter. Therefore,
as shown in Fig. 17, the gradient formed in the blade inside diameter of the blades 12
allows the multi-blade air-sending device 100C to ensure a wide area of the leading
edges of the blades 12 relative to a flow of gas, so that air can pass through the
impeller 10C with low ventilation resistance. As a result, the multi-blade air-sending
25 device 100C can increase air-sending efficiency.
[0090]
Angles of inclination of the inclined portions 141A and 141B of the multi-blade
air-sending device 100C may be set as appropriate. Although increasing the angles
of inclination of the inclined portions 141A and 141B makes it possible to ensure a
30 wide area of the leading edges of the blades 12 relative to a flow of gas, it is
45
necessary to increase the sizes of the impeller 10C and the multi-blade air-sending
device 100C in the radial direction to increase the angles of inclination while ensuring
the predetermined blade height WH. To ensure a wide area of the leading edges of
the blades 12 while suppressing upsizing of the impeller 10C and the multi-blade air5 sending device 100C, it is desirable to set the angles of inclination of the inclined
portions 141A and 141B to be smaller than or equal to 60 degrees. Further, to
achieve a further reduction in size of the impeller 10C and the multi-blade air-sending
device 100C, it is desirable to set the angles of inclination of the inclined portions
141A and 141B to be smaller than or equal to 45 degrees.
10 [0091]
[Multi-blade Air-sending Device 100D]
Fig. 18 is a cross-sectional view of a multi-blade air-sending device 100D
according to a first modification of the multi-blade air-sending device 100C shown in
Fig. 15. The multi-blade air-sending device 100D according to the first modification
15 of the multi-blade air-sending device 100C according to Embodiment 2 is described
with reference to Fig. 18. It should be noted that components having identical
configurations as those of the multi-blade air-sending device 100 or other devices of
Figs. 1 to 17 are given identical signs and a description of such elements is omitted.
An impeller 10D of the multi-blade air-sending device 100D is intended to further
20 specify the configuration of the leading edges 14A1 and 14B1 of the plurality of
blades 12 of the impeller 10C of the multi-blade air-sending device 100C according to
Embodiment 2. Accordingly, in the following description, the impeller 10D is
described with reference to Fig. 18 with a focus on a configuration of the leading
edges 14A1 and 14B1 of the multi-blade air-sending device 100D.
25 [0092]
As mentioned above, the plurality of blades 12 form an inclined portion 141A
inclined such that the leading edges 14A1 extend away from the rotation axis RS so
that the blade inside diameter increases from the backing plate 11 toward the rim 13.
Similarly, the plurality of blades 12 form an inclined portion 141B inclined such that
30 the leading edges 14B1 extend away from the rotation axis RS so that the blade
46
inside diameter increases from the backing plate 11 toward the rim 13. The plurality
of blades 12 have gradients formed on the inner circumference by the inclined portion
141A and the inclined portion 141B.
[0093]
5 The inclined portion 141A is inclined relative to the rotation axis RS. The
inclined portion 141A has an angle of inclination preferably larger than 0 degree and
smaller than or equal to 60 degrees or more preferably larger than 0 degree and
smaller than or equal to 45 degrees. That is, an angle of inclination 1 between the
inclined portion 141A and the rotation axis RS is configured to preferably satisfy the
10 relationship "0 degree < 1  60 degrees" or more preferably satisfy the relationship
"0 degree < 1  45 degrees". Similarly, the inclined portion 141B is inclined relative
to the rotation axis RS. The inclined portion 141B has an angle of inclination
preferably larger than 0 degree and smaller than or equal to 60 degrees or more
preferably larger than 0 degree and smaller than or equal to 45 degrees. That is, an
15 angle of inclination 2 between the inclined portion 141B and the rotation axis RS is
configured to preferably satisfy the relationship "0 degree < 2  60 degrees" or more
preferably satisfy the relationship "0 degree < 2  45 degrees".
[0094]
The blade height WH shown in Fig. 18 is less than or equal to 200 mm. The
20 blade height WH is the distance between the backing plate 11 and end portions 12t of
the plurality of blades 12 in the axial direction of the rotation axis RS, and is the
maximum distance between the backing plate 11 and the end portions 12t of the
plurality of blades 12 in the axial direction of the rotation axis RS. The blade height
WH is not limited to being less than or equal to 200 mm but may be greater than 200
25 mm.
[0095]
The plurality of blades 12 have linear portions 141C1 provided at the leading
edges 14A1 between the backing plate 11 and the rim 13. The linear portions
141C1 are provided beside the backing plate 11 between the backing plate 11 and the
30 rim 13. Accordingly, the leading edge 14A1 of a first blade 12A is formed by a linear
47
portion 141C1 provided beside the backing plate 11 and an inclined portion 141A
provided beside the rim 13. The impeller 10D of the multi-blade air-sending device
100D is configured such that an inside diameter IDc1 formed by the linear portions
141C1 of the leading edges 14A1 has a certain size in the axial direction of the
5 rotation axis RS.
[0096]
Similarly, the plurality of blades 12 have linear portions 141C2 provided at the
leading edges 14B1 between the backing plate 11 and the rim 13. The linear
portions 141C2 are provided beside the backing plate 11 between the backing plate
10 11 and the rim 13 . Accordingly, the leading edge 14B1 of a second blade 12B is
formed by a linear portion 141C2 provided beside the backing plate 11 and an
inclined portion 141B provided beside the rim 13. The impeller 10D of the multiblade air-sending device 100D is configured such that an inside diameter IDc2 formed
by the linear portions 141C2 of the leading edges 14B1 has a certain size in the axial
15 direction of the rotation axis RS.
[0097]
[Working Effects of Impeller 10D and Multi-blade Air-sending Device 100D]
As shown in Fig. 18, the multi-blade air-sending device 100D has an inclined
portion 141A and an inclined portion 141B at the leading edges of the blades 12, and
20 has a gradient formed in the blade inside diameter. Therefore, the gradient formed
in the blade inside diameter of the blades 12 allows the multi-blade air-sending device
100D to ensure a wide area of the leading edges of the blades 12 relative to a flow of
gas, so that air can pass through the impeller 10D with low ventilation resistance. As
a result, the multi-blade air-sending device 100D can increase air-sending efficiency.
25 [0098]
[Multi-blade Air-sending Device 100E]
Fig. 19 is a cross-sectional view of a multi-blade air-sending device 100E
according to a second modification of the multi-blade air-sending device 100C shown
in Fig. 15. The multi-blade air-sending device 100E according to the second
30 modification of the multi-blade air-sending device 100C according to Embodiment 2 is
48
described with reference to Fig. 19. It should be noted that elements having
identical configurations as those of the multi-blade air-sending device 100 or other
devices of Figs. 1 to 18 are given identical signs and a description of such elements is
omitted. An impeller 10E of the multi-blade air-sending device 100E is intended to
5 further specify the configuration of the leading edges 14A1 and 14B1 of the plurality
of blades 12 of the impeller 10C of the multi-blade air-sending device 100C according
to Embodiment 2. Accordingly, in the following description, the impeller 10E is
described with reference to Fig. 19 with a focus on a configuration of the leading
edges 14A1 and 14B1 of the multi-blade air-sending device 100E.
10 [0099]
As mentioned above, the plurality of blades 12 form an inclined portion 141A
inclined such that the leading edges 14A1 extend away from the rotation axis RS so
that a blade inside diameter IDe increases from the backing plate 11 toward the rim
13. Further, the plurality of blades 12 form an inclined portion 141A2 inclined such
15 that the leading edges 14A1 extend away from the rotation axis RS so that the blade
inside diameter IDe increases from the backing plate 11 toward the rim 13. The
inclined portion 141A2 is provided beside the backing plate 11 between the backing
plate 11 and the rim 13. Accordingly, the leading edge 14A1 of a first blade 12A is
formed by a inclined portion 141A2 provided beside the backing plate 11 and an
20 inclined portion 141A provided beside the rim 13. That is, a first blade 12A of the
plurality of blades 12 has two inclined portions, namely an inclined portion 141A and
an inclined portion 141A2, between the backing plate 11 and the rim 13. A first blade
12A of the plurality of blades 12 is not limited to being configured to have two inclined
portions, namely an inclined portion 141A and an inclined portion 141A2, but needs
25 only have two or more inclined portions.
[0100]
Similarly, the plurality of blades 12 form an inclined portion 141B inclined such
that the leading edges 14B1 extend away from the rotation axis RS so that the blade
inside diameter IDe increases from the backing plate 11 toward the rim 13. Further,
30 the plurality of blades 12 form an inclined portion 141B2 inclined such that the leading
49
edges 14B1 extend away from the rotation axis RS so that the blade inside diameter
IDe increases from the backing plate 11 toward the rim 13. The inclined portion
141B2 is provided beside the backing plate 11 between the backing plate 11 and the
rim 13. Accordingly, the leading edge 14B1 of a second blade 12B is formed by an
5 inclined portion 141B2 provided beside the backing plate 11 and an inclined portion
141B provided beside the rim 13. That is, a second blade 12B of the plurality of
blades 12 has two inclined portions, namely an inclined portion 141B and an inclined
portion 141B2, between the backing plate 11 and the rim 13. A second blade 12B of
the plurality of blades 12 is not limited to being configured to have two inclined
10 portions, namely an inclined portion 141B and an inclined portion 141B2, but needs
only have two or more inclined portions. The plurality of blades 12 have gradients
formed on the inner circumference by the inclined portion 141A, the inclined portion
141A2, the inclined portion 141B, and the inclined portion 141B2.
[0101]
15 At least either the inclined portion 141A or the inclined portion 141A2 is inclined
relative to the rotation axis RS. The inclined portion 141A and/or the inclined portion
141A2 has/have an angle of inclination preferably larger than 0 degree and smaller
than or equal to 60 degrees or more preferably larger than 0 degree and smaller than
or equal to 45 degrees. That is, an angle of inclination 1 between the inclined
20 portion 141A and the rotation axis RS is configured to preferably satisfy the
relationship "0 degree < 1  60 degrees" or more preferably satisfy the relationship
"0 degree < 1  45 degrees". Alternatively, an angle of inclination 11 between the
inclined portion 141A2 and the rotation axis RS is configured to preferably satisfy the
relationship "0 degree < 11  60 degrees" or more preferably satisfy the relationship
25 "0 degree < 11  45 degrees". In Fig. 19, the virtual line VL3 is a virtual line parallel
with the rotation axis RS. Therefore, an angle between the inclined portion 141A2
and the virtual line VL3 is equal to the angle between the inclined portion 141A2 and
the rotation axis RS.
[0102]
30 The angle of inclination 1 of the inclined portion 141A and the angle of
50
inclination 11 of the inclined portion 141A2 are different angles. In a case in which
a first blade 12A has two or more inclined portions, the angle of inclination of each
inclined portion is different from that of the other. There is no limit on a relationship
between the magnitude of the angle of inclination 1 of the inclined portion 141A and
5 the magnitude of the angle of inclination 11 of the inclined portion 141A2. For
example, as shown in Fig. 19, the magnitude of the angle of inclination 11 of the
inclined portion 141A2 of a first blade 12A may be greater than the magnitude of the
angle of inclination 1 of the inclined portion 141A of the first blade 12A.
Alternatively, the magnitude of the angle of inclination 11 of the inclined portion
10 141A2 of a first blade 12A may be smaller than the magnitude of the angle of
inclination 1 of the inclined portion 141A of the first blade 12A.
[0103]
Similarly, at least either the inclined portion 141B or the inclined portion 141B2
is inclined relative to the rotation axis RS. The inclined portion 141B and/or the
15 inclined portion 141B2 has/have an angle of inclination preferably larger than 0
degree and smaller than or equal to 60 degrees or more preferably larger than 0
degree and smaller than or equal to 45 degrees. That is, an angle of inclination 2
between the inclined portion 141B and the rotation axis RS is configured to preferably
satisfy the relationship "0 degree < 2  60 degrees" or more preferably satisfy the
20 relationship "0 degree < 2  45 degrees". Alternatively, an angle of inclination 22
between the inclined portion 141B2 and the rotation axis RS is configured to
preferably satisfy the relationship "0 degree < 22  60 degrees" or more preferably
satisfy the relationship "0 degree < 22  45 degrees". In Fig. 19, the virtual line VL4
is a virtual line parallel with the rotation axis RS. Therefore, an angle between the
25 inclined portion 141B2 and the virtual line VL4 is equal to the angle between the
inclined portion 141B2 and the rotation axis RS.
[0104]
The angle of inclination 2 of the inclined portion 141B and the angle of
inclination 22 of the inclined portion 141B2 are different angles. In a case in which
30 a second blade 12B has two or more inclined portions, the angle of inclination of each
51
inclined portion is different from that of the other. There is no limit on a relationship
between the magnitude of the angle of inclination 2 of the inclined portion 141B and
the magnitude of the angle of inclination 22 of the inclined portion 141B2. For
example, as shown in Fig. 19, the magnitude of the angle of inclination 22 of the
5 inclined portion 141B2 of a second blade 12B may be greater than the magnitude of
the angle of inclination 2 of the inclined portion 141B of the second blade 12B.
Alternatively, the magnitude of the angle of inclination 22 of the inclined portion
141B2 of a second blade 12B may be smaller than the magnitude of the angle of
inclination 2 of the inclined portion 141B of the second blade 12B.
10 [0105]
The blade height WH shown in Fig. 19 is less than or equal to 200 mm. The
blade height WH is the distance between the backing plate 11 and end portions 12t of
the plurality of blades 12 in the axial direction of the rotation axis RS, and is the
maximum distance between the backing plate 11 and the end portions 12t of the
15 plurality of blades 12 in the axial direction of the rotation axis RS. The blade height
WH is not limited to being less than or equal to 200 mm but may be greater than 200
mm.
[0106]
[Working Effects of Impeller 10E and Multi-blade Air-sending Device 100E]
20 As shown in Fig. 19, the multi-blade air-sending device 100E has an inclined
portion 141A, an inclined portion 141A2, an inclined portion 141B, and an inclined
portion 141B2 at the leading edges of the blades 12, and has a gradient formed in the
blade inside diameter IDe. Therefore, the gradient formed in the blade inside
diameter IDe of the blades 12 allows the multi-blade air-sending device 100E to
25 ensure a wide area of the leading edges of the blades 12 relative to a flow of gas, so
that air can pass through the impeller 10E with low ventilation resistance. As a
result, the multi-blade air-sending device 100E can increase air-sending efficiency.
[0107]
Embodiment 3
30 [Multi-blade Air-sending Device 100F]
52
Fig. 20 is a schematic view illustrating a relationship between a bellmouth 46
and a blade 12 of a multi-blade air-sending device 100F according to Embodiment 3.
Fig. 21 is a schematic view illustrating a relationship between a bellmouth 46 and a
blade 12 of a modification of the multi-blade air-sending device 100F according to
5 Embodiment 3. The multi-blade air-sending device 100F according to Embodiment
3 is described with reference to Figs. 20 and 21. It should be noted that elements
having identical configurations as those of the multi-blade air-sending device 100 or
other devices of Figs. 1 to 19 are given identical signs and a description of such
elements is omitted. An impeller 10F of the multi-blade air-sending device 100F
10 according to Embodiment 3 is intended to further specify the configuration of the turbo
blade portions of the impeller 10 of the multi-blade air-sending device 100 according
to Embodiment 1. Accordingly, in the following description, the impeller 10F is
described with reference to Figs. 20 and 21 with a focus on a configuration of the
turbo blade portions of the multi-blade air-sending device 100F according to
15 Embodiment 3.
[0108]
The impeller 10F of the multi-blade air-sending device 100F according to
Embodiment 3 has a step portion 12D formed at an end portion 12t of a turbo blade
portion facing the rim 13. In the following, as shown in Fig. 20, the step portion 12D
20 is described with reference to a first blade 12A. The step portion 12D is formed at
an end portion 12t of the first turbo blade portion 12A2 facing the rim 13. That is, the
step portion 12D is formed at an end portion 12t of the inclined portion 141A facing
the rim 13. The step portion 12D is a portion in which a wall forming the first blade
12A is formed in a notched state. The step portion 12D is a portion in which a
25 portion of joining between the leading edge 14A1 of the first blade 12A and the end
portion 12t of the first turbo blade portion 12A2 facing the rim 13 is formed in a
notched state. The step portion 12D is formed by a side edge portion 12D1
extending in the axial direction of the rotation axis RS of the impeller 10F and an
upper edge portion 12D2 extending in the radial direction of the impeller 10F. Note,
30 however, that the step portion 12D is not limited to being configured to be formed by a
53
side edge portion 12D1 extending in the axial direction of the rotation axis RS of the
impeller 10F and an upper edge portion 12D2 extending in the radial direction of the
impeller 10F. For example, the step portion 12D may be formed as an arc-shaped
edge portion formed by a continuously-integrated combination of a side edge portion
5 12D1 and an upper edge portion 12D2.
[0109]
A second blade 12B has a step portion 12D formed therein, too, although the
step portion 12D of the second blade 12B is not illustrated, as it is similar in
configuration to that of the first blade 12A. The step portion 12D is formed at an end
10 portion 12t of the second turbo blade portion 12B2 facing the rim 13, too. That is,
the step portion 12D is formed at an end portion 12t of the inclined portion 141B
facing the rim 13. The step portion 12D is a portion in which a wall forming the
second blade 12B is formed in a notched state. The step portion 12D is a portion in
which a portion of joining between the leading edge 14B1 of the second blade 12B
15 and the end portion 12t of the second turbo blade portion 12B2 facing the rim 13 is
formed in a notched state.
[0110]
The plurality of blades 12 of the multi-blade air-sending device 100F according
to Embodiment 3 are formed such that a blade outside diameter formed by the outer
20 circumferential end of each of the plurality of blades 12 is larger than the inside
diameter BI of the bellmouth 46. Moreover, as shown in Figs. 20 and 21, the multiblade air-sending device 100F is configured such that an inner circumferential end
portion 46b of the bellmouth 46 is disposed above the step portion 12D. The multiblade air-sending device 100F is configured such that the inner circumferential end
25 portion 46b of the bellmouth 46 is disposed so as to face the upper edge portion
12D2 of the step portion 12D. The multi-blade air-sending device 100F has a gap
formed between the inner circumferential end portion 46b of the bellmouth 46 and the
side edge portion 12D1 and between the inner circumferential end portion 46b of the
bellmouth 46 and the upper edge portion 12D2.
30 [0111]
54
[Working Effects of Impeller 10F and Multi-blade Air-sending Device 100F]
The impeller 10F and the multi-blade air-sending device 100F have a step
portion formed at an end portion 12t of a turbo blade portion facing the rim 13. The
step portion 12D allows the impeller 10F and the multi-blade air-sending device 100F
5 to widen the gap between a bellmouth 46 and a blade 12. Therefore, the impeller
10F and the multi-blade air-sending device 100F can suppress an increase in velocity
of a flow of gas in the gap between the bellmouth 46 and the blade 12, thus making it
possible to reduce noise generated by the flow of gas passing through the gap
between the bellmouth 46 and the blade 12.
10 [0112]
Further, the impeller 10F and the multi-blade air-sending device 100F allow the
bellmouth 46 to be brought closer to the impeller 10F than in a case in which a blade
12 has no step portion 12D. Moreover, the impeller 10F and the multi-blade airsending device 100F can reduce the gap between the bellmouth 46 and the blade 12
15 by bringing the bellmouth 46 close to the impeller 10F. As a result, the impeller 10F
and the multi-blade air-sending device 100F can reduce leakage of suctioned air, that
is, the amount of air that does not pass through the space between adjacent blades
12 of the impeller 10F. Since the bellmouth 46 and the side edge portion 12D1 are
disposed so as to face each other as shown in Fig. 21, the impeller 10F and the multi20 blade air-sending device 100F can further reduce leakage of suctioned air than in a
case in which the bellmouth 46 and the side edge portion 12D1 do not face each
other. In other words, since the bellmouth 46 is disposed within the step portion 12D
and disposed above and in the radial direction of the blade 12, the multi-blade airsending device 100F can further reduce leakage of suctioned air than in a case in
25 which the bellmouth 46 is not disposed within the step portion 12D.
[0113]
Embodiment 4.
[Multi-blade Air-sending Device 100G]
Fig. 22 is a cross-sectional view schematically illustrating a multi-blade air30 sending device 100G according to Embodiment 4. Fig. 23 is a schematic view of
55
blades 12 as viewed from an angle parallel with a rotation axis RS in an impeller 10G
of Fig. 22. Fig. 24 is a schematic view of the blades 12 in a cross-section of the
impeller 10G as taken along line D-D in Fig. 22. The multi-blade air-sending device
100G according to Embodiment 4 is described with reference to Figs. 22 to 24. It
5 should be noted that elements having identical configurations as those of the multiblade air-sending device 100 or other devices of Figs. 1 to 21 are given identical
signs and a description of such elements is omitted.
[0114]
As shown in Figs. 22 to 24, the impeller 10G of the multi-blade air-sending
10 device 100G according to Embodiment 4 is configured such that all of the plurality of
blades 12 are formed by first blades 12A. As shown in Figs. 22 to 24, the impeller
10G has forty-two first blades 12A disposed therein. However, the number of first
blades 12A is not limited to 42 but may be smaller or larger than 42.
[0115]
15 Each of the first blades 12A has the relationship "Blade Length L1a > Blade
Length L1b". That is, each of the first blades 12A is formed such that its blade length
decreases from the backing plate 11 toward the rim 13 in the axial direction of the
rotation axis RS. Moreover, as shown in Fig. 22, each of the first blades 12A is
inclined such that a blade inside diameter IDg increases from the backing plate 11
20 toward the rim 13. That is, the plurality of blades 12 form an inclined portion 141A
inclined such that the inner circumferential ends 14A forming the leading edges 14A1
extend away from the rotation axis RS so that the blade inside diameter IDg
increases from the backing plate 11 toward the rim 13.
[0116]
25 Each of the first blades 12A has a first sirocco blade portion 12A1 being
forward-swept and a first turbo blade portion 12A2 being swept-back. Each of the
first blades 12A is configured such that the first turbo region 12A21 is larger than the
first sirocco region 12A11 in the radial direction of the impeller 10. That is, the
impeller 10 and each of the first blades 12A are configured such that in both the
30 backing-plate-side blade region 122a serving as the first region and the rim-side
56
blade region 122b serving as the second region, a ratio of the first turbo blade portion
12A2 is larger than a ratio of the first sirocco blade portion 12A1 in the radial direction
of the impeller 10.
[0117]
5 When a spacing between two of the plurality of blades 12 adjacent to each
other in the circumferential direction is defined as a blade spacing, the blade spacing
between a plurality of blades 12 widens from the leading edges 14A1 toward the
trailing edges 15A1 as shown in Figs. 23 and 24. Specifically, a blade spacing in the
first turbo blade portion 12A2 widens from the inner circumference toward the outer
10 circumference. Moreover, a blade spacing in a first sirocco blade portion 12A1 is
wider than the blade spacing in the first turbo blade portion 12A2 and widens from the
inner circumference toward the outer circumference.
[0118]
As shown in Fig. 22, the inside diameter BI of the bellmouth 46 is larger than
15 the inside diameter ID1a of the first blades 12A beside the backing plate 11 and
smaller than the inside diameter ID3a of the first blades 12A beside the rim 13. That
is, the inside diameter BI of the bellmouth 46 is to be larger than the blade inside
diameter IDg of the plurality of blades 12 beside the backing plate 11 and smaller
than the blade inside diameter IDg of the plurality of blades 12 beside the rim 13.
20 [0119]
[Working Effects of Impeller 10G and Multi-blade Air-sending Device 100G]
The impeller 10G and the multi-blade air-sending device 100G can bring about
effects similar to those of the multi-blade air-sending device 100 and the impeller 10
according to Embodiment 1. For example, the impeller 10G and the multi-blade air25 sending device 100G are configured such that in any region between the backing
plate 11 and the rim 13, a ratio of a region of the first turbo blade portion 12A2 in the
radial direction of the backing plate 11 is larger than a ratio of a region of the first
sirocco blade portion 12A1 in the radial direction of the backing plate 11. Since the
impeller 10G and the multi-blade air-sending device 100G are configured such that
30 the ratio of the turbo blade portion is high in any region between the backing plate 11
57
and the rim 13, sufficient pressure recovery can be achieved through the plurality of
blades 12. Therefore, the impeller 10G and the multi-blade air-sending device 100G
can better improve pressure recovery than an impeller or a multi-blade air-sending
device that does not include such a configuration. As a result, the impeller 10G can
5 improve the efficiency of the multi-blade air-sending device 100G. Furthermore, by
including the foregoing configuration, the impeller 10G can reduce leading edge
separation of a flow of gas beside the rim 13.
[0120]
Embodiments 1 to 4 have been described by taking as an example a multi10 blade air-sending device 100 including a double-suction impeller 10 having a plurality
of blades 12 formed on both sides of a backing plate 11. However, Embodiments 1
to 4 are also applicable to a multi-blade air-sending device 100 including a singlesuction impeller 10 having a plurality of blades 12 formed only on one side of a
backing plate 11.
15 [0121]
Embodiment 5
[Air-conditioning Apparatus 140]
Fig. 25 is a perspective view of an air-conditioning apparatus 140 according to
Embodiment 5. Fig. 26 is a diagram illustrating an internal configuration of the air20 conditioning apparatus 140 according to Embodiment 5. As for a multi-blade airsending device 100 used in the air-conditioning apparatus 140 according to
Embodiment 5, elements having identical configurations as those of the multi-blade
air-sending device 100 or other devices of Figs. 1 to 24 are given identical signs, and
a description of such elements is omitted. To show the internal configuration of the
25 air-conditioning apparatus 140, Fig. 26 omits to illustrate an upper surface portion
16a.
[0122]
The air-conditioning apparatus 140 according to Embodiment 5 includes any
one or more of the multi-blade air-sending devices 100 to 100G according to
30 Embodiments 1 to 4 and a heat exchanger 15 disposed in such a location as to face a
58
discharge port 42a of the multi-blade air-sending device 100. Further, the airconditioning apparatus 140 according to Embodiment 5 includes a case 16 installed
above a ceiling of a room to be air-conditioned. In the following description, the term
"multi-blade air-sending device 100" indicates the use of any one of the multi-blade
5 air-sending devices 100 to 100G according to Embodiments 1 to 4. Further,
although, in Figs. 26 and 25, a multi-blade air-sending device 100 having a scroll
casing 40 in the case 16 is shown, impellers 10 to 10G or other devices having no
scroll casing 40 may be installed in the case 16.
[0123]
10 (Case 16)
As shown in Fig. 25, the case 16 is formed in a cuboidal shape including an
upper surface portion 16a, a lower surface portion 16b, and side surface portions 16c.
The shape of the case 16 is not limited to the cuboidal shape but may for example be
another shape such as a columnar shape, a prismatic shape, a conical shape, a
15 shape having a plurality of corner portions, or a shape having a plurality of curved
surface portions. One of the side surface portions 16c of the case 16 is a side
surface portion 16c having a case discharge portion 17 formed therein. The case
discharge portion 17 is formed in a rectangular shape as shown in Fig. 25. The
shape of the case discharge port 17 is not limited to the rectangular shape but may
20 for example be another shape such as a circular shape or an oval shape. Another
one of the side surface portions 16c of the case 16 is a side surface portion 16c
having a case air inlet 18 formed therein and being opposite the side surface portion
16c having the case discharge port 17 formed therein. The case air inlet 18 is
formed in a rectangular shape as shown in Fig. 26. The shape of the case air inlet
25 18 is not limited to the rectangular shape but may for example be another shape such
as a circular shape or an oval shape. A filter configured to remove dust in the air
may be disposed at the case air inlet 18.
[0124]
Inside the case 16, the multi-blade air-sending device 100 and the heat
30 exchanger 15 are housed. The multi-blade air-sending device 100 includes an
59
impeller 10, a scroll casing 40 having a bellmouth 46 formed therein, and a motor 50.
The motor 50 is supported by a motor support 9a fixed to the upper surface portion
16a of the case 16. The motor 50 has a motor shaft 51. The motor shaft 51 is
disposed so as to extend parallel to the side surface portion 16c having the case air
5 inlet 18 formed therein and the side surface portion 16c having the case discharge
port 17 formed therein. As shown in Fig. 26, the air-conditioning apparatus 140 has
two impellers 10 attached to the motor shaft 51. The impellers 10 of the multi-blade
air-sending device 100 forms a flow of air that is suctioned into the case 16 through
the case air inlet 18 and blown out into an air-conditioned space through the case
10 discharge port 17. The number of impellers 10 that are disposed in the case 16 is
not limited to 2 but may be 1 or larger than or equal to 3.
[0125]
As shown in Fig. 26, the multi-blade air-sending device 100 is attached to a
divider 19 configured to divide an internal space of the case 16 into a space S11
15 facing a suction side of the scroll casing 40 and a space S12 facing a blowout side of
the scroll casing 40.
[0126]
The heat exchanger 15 is disposed in such a location as to face the discharge
port 42a of the multi-blade air-sending device 100, and is disposed in the case 16 so
20 as to be on an air trunk of air to be discharged by the multi-blade air-sending device
100. The heat exchanger 15 adjusts the temperature of air that is suctioned into the
case 16 through the case air inlet 18 and blown out into the air-conditioned space
through the case discharge port 17. As the heat exchanger 15, a heat exchanger of
a publicly-known structure can be applied. The case air inlet 18 needs only be
25 formed in a location perpendicular to the axial direction of the rotation axis RS of the
multi-blade air-sending device 100. For example, the case air inlet 18 may be
formed in the lower surface portion 16b.
[0127]
Rotation of the impeller 10 of the multi-blade air-sending device 100 causes the
30 air in the air-conditioned space to be suctioned into the case 16 through the case air
60
inlet 18. The air suctioned into the case 16 is guided toward the bellmouth 46 and
suctioned into the impeller 10. The air suctioned into the impeller 10 is blown out
outward in the radial direction of the impeller 10. The air blown out from the impeller
10 passes through the inside of the scroll casing 40, blown out of the scroll casing 40
5 through the discharge port 42a, and then supplied to the heat exchanger 15. The air
supplied to the heat exchanger 15 is subjected to temperature and humidity control
by, during passage through the heat exchanger 15, exchanging heat with refrigerant
flowing through the inside of the heat exchanger 15. The air having passed through
the heat exchanger 15 is blown out to the air-conditioned space through the case
10 discharge port 17.
[0128]
The air-conditioning apparatus 140 according to Embodiment 5 includes any
one of the multi-blade air-sending devices 100 to 100G according to Embodiments 1
to 4. Therefore, the air-conditioning apparatus 140 can bring about effects similar to
15 those of any of Embodiments 1 to 4.
[0129]
Each of Embodiment 1 to 5 may be implemented in combination with the other.
Further, the configurations shown in the foregoing embodiments show examples and
may be combined with another publicly-known technology, and parts of the
20 configurations may be omitted or changed, provided such omissions and changes do
not depart from the scope. For example, an embodiment describes an impeller 10 or
other devices formed by the backing-plate-side blade region 122a serving as the first
region and the rim-side blade region 122b serving as the second region. The
impeller 10 is not limited to an impeller formed solely by the first region and the
25 second region. The impeller 10 may further have another region as well as the first
region and the second region. For example, although, in Embodiment 1, each of the
blades are shaped such that the blade length continuously changes from the backing
plate 11 toward the rim 13, each of the blades may have, in some part between the
backing plate 11 and the rim 13, a portion in which the blade length is constant, that
30 is, a portion in which the inside diameter ID is constant and that is not inclined relative
61
to the rotation axis RS.
Reference Signs List
[0130]
9a: motor support, 10: impeller, 10C: impeller, 10D: impeller, 10E: impeller,
5 10F: impeller, 10G: impeller, 10H: impeller, 10e: air inlet, 11: backing plate, 11b: shaft
portion, 12: blade, 12A: first blade, 12A1: first sirocco blade portion, 12A11: first
sirocco region, 12A2: first turbo blade portion, 12A21: first turbo region, 12A21a: first
turbo region, 12A2a: first turbo blade portion, 12A3: first radial blade portion, 12B:
second blade, 12B1: second sirocco blade portion, 12B11: second sirocco region,
10 12B2: second turbo blade portion, 12B21: second turbo region, 12B21a: second turbo
region, 12B2a: second turbo blade portion, 12B3: second radial blade portion, 12D:
step portion, 12D1: side edge portion, 12D2: upper edge portion, 12R: outer
circumferential region, 12t: end portion, 13: rim, 13a: first rim, 13b: second rim, 14A:
inner circumferential end, 14A1: leading edge, 14B: inner circumferential end, 14B1:
15 leading edge, 14H: leading edge, 15: heat exchanger, 15A: outer circumferential end,
15A1: trailing edge, 15B: outer circumferential end, 15B1: trailing edge, 16: case, 16a:
upper surface portion, 16b: lower surface portion, 16c: side surface portion, 17: case
discharge port, 18: case air inlet, 19: divider, 40: scroll casing, 41: scroll portion, 41a:
scroll start portion, 41b: scroll end portion, 42: discharge portion, 42a: discharge port,
20 42b: extension plate, 42c: diffuser plate, 42d: first side plate portion, 42e: second side
plate portion, 43: tongue, 44a: side wall, 44a1: first side wall, 44a2: second side wall,
44c: peripheral wall, 45: air inlet, 45a: first air inlet, 45b: second air inlet, 46:
bellmouth, 46a: opening, 46b: inner peripheral end portion, 50: motor, 50A: motor,
50B: motor, 50a: end portion, 51: motor shaft, 52: outer peripheral wall, 52a: outer
25 peripheral wall, 52b: outer peripheral wall, 71: first plane, 72: second plane, 100:
multi-blade air-sending device, 100A: multi-blade air-sending device, 100B: multiblade air-sending device, 100C: multi-blade air-sending device, 100D: multi-blade airsending device, 100E: multi-blade air-sending device, 100F: multi-blade air-sending
device, 100G: multi-blade air-sending device, 100H: multi-blade air-sending device,
30 112a: first blade portion, 112b: second blade portion, 122a: backing-plate-side blade
62
region, 122b: rim-side blade region, 140: air-conditioning apparatus, 141A: inclined
portion, 141A2: inclined portion, 141B: inclined portion, 141B2: inclined portion,
141C1: linear portion, 141C2: linear portion
63
We Claim :
[Claim 1]
An impeller comprising:
a backing plate configured to be driven by rotating;
5 an annular rim disposed so as to face the backing plate; and
a plurality of blades arranged in a circumferential direction around a virtual
rotation axis of the backing plate, one end of each of the plurality of blades being
connected with the backing plate, an other end of each of the plurality of blades being
connected with the rim;
10 each of the plurality of blades having
an inner circumferential end located closer to the rotation axis in a radial
direction around the rotation axis,
an outer circumferential end located closer to an outer circumference
than the inner circumferential end in the radial direction,
15 a sirocco blade portion being forward-swept and including the outer
circumferential end and having a blade outlet angle of larger than 90 degrees, and
a turbo blade portion being swept-back and including the inner
circumferential end,
a first region located closer to the backing plate than a middle point in an
20 axial direction of the rotation axis, and
a second region located closer to the rim than the first region,
each of the plurality of blades being formed such that a blade length in the first
region is longer than a blade length in the second region,
in the first region and the second region, a ratio of the turbo blade portion in the
25 radial direction being larger than a ratio of the sirocco blade portion in the radial
direction.
[Claim 2]
The impeller of claim 1, wherein each of the plurality of blades has an inclined
portion inclined such that the inner circumferential end extends away from the rotation
30 axis from the backing plate toward the rim.
64
[Claim 3]
The impeller of claim 2, wherein the inclined portion is inclined at an angle of
larger than 0 degree and smaller than or equal to 60 degrees relative to the rotation
axis.
5 [Claim 4]
The impeller of any one of claims 1 to 3, wherein a ratio of a blade inside
diameter formed by the inner circumferential end of each of the plurality of blades to a
blade outside diameter formed by the outer circumferential end of each of the plurality
of blades is lower than or equal to 0.7.
10 [Claim 5]
The impeller of any one of claims 1 to 4, wherein
when a spacing between two of the plurality of blades adjacent to each other in
the circumferential direction is defined as a blade spacing, a blade spacing of the
turbo blade portion widens from an inner circumference toward the outer
15 circumference in the radial direction, and
a blade spacing of the sirocco blade portion is wider than the blade spacing of
the turbo blade portion and widens from the inner circumference toward the outer
circumference in the radial direction.
[Claim 6]
20 The impeller of any one of claims 1 to 5, wherein the turbo blade portion
linearly extends from the inner circumferential end toward the outer circumference in
the radial direction.
[Claim 7]
The impeller of any one of claims 1 to 6, wherein each of the plurality of blades
25 has a radial blade portion serving as a portion of connection between the turbo blade
portion and the sirocco blade portion and having a blade angle of 90 degrees.
[Claim 8]
The impeller of any one of claims 1 to 7, wherein
the plurality of blades include a plurality of first blades and a plurality of second
30 blades,
65
in a first cross-section of the plurality of blades as taken along a first plane
perpendicular to the rotation axis in the first region, each of the plurality of first blades
has a blade length longer than a blade length of each of the plurality of second
blades, and
5 at least one of the plurality of second blades is disposed between two of the
plurality of first blades adjacent to each other in the circumferential direction.
[Claim 9]
The impeller of claim 8, wherein the plurality of second blades are configured
such that a ratio of an inside diameter formed by the inner circumferential end of each
10 of the plurality of second blades to an outside diameter formed by the outer
circumferential end of each of the plurality of second blades is lower than or equal to
0.7.
[Claim 10]
A multi-blade air-sending device comprising:
15 the impeller of any one of claims 1 to 9; and
a scroll casing housing the impeller and having a peripheral wall formed into a
volute shape and a side wall having a bellmouth forming an air inlet communicating
with a space formed by the backing plate and the plurality of blades.
[Claim 11]
20 The multi-blade air-sending device of claim 10, wherein
the plurality of blades are formed such that a blade outside diameter formed by
the outer circumferential end of each of the plurality of blades is larger than an inside
diameter of the bellmouth, and
in a portion of the plurality of blades situated closer to the outer circumference
25 than the inside diameter of the bellmouth in the radial direction, a ratio of the turbo
blade portion in the radial direction is larger than a ratio of the sirocco blade portion in
the radial direction in both the first region and the second region.
[Claim 12]
The multi-blade air-sending device of claim 10 or 11, wherein
30 the plurality of blades are formed such that a blade outside diameter formed by
66
the outer circumferential end of each of the plurality of blades is larger than an inside
diameter of the bellmouth, and
each of the plurality of blades has a step portion formed at an end portion of
the turbo blade portion facing the rim.
5 [Claim 13]
The multi-blade air-sending device of any one of claims 10 to 12, wherein an
inside diameter of the bellmouth is formed to be larger than a blade inside diameter
formed by the inner circumferential end of each of the plurality of blades in the first
region and smaller than a blade inside diameter formed by the inner circumferential
10 end of each of the plurality of blades in the second region.
[Claim 14]
The multi-blade air-sending device of any one of claims 10 to 13, wherein a
shortest distance between the plurality of blades and the peripheral wall is more than
twice as long as a radial length of the sirocco blade portion.
15 [Claim 15]
The multi-blade air-sending device of any one of claims 10 to 14, further
comprising a motor having a motor shaft connected to the backing plate and being
disposed outside the scroll casing,
an outside diameter of the motor is formed to be larger than a blade inside
20 diameter of the plurality of blades beside the backing plate and smaller than a blade
inside diameter of the plurality of blades beside the rim.
[Claim 16]
The multi-blade air-sending device of any one of claims 10 to 14, further
comprising a motor having a motor shaft connected to the backing plate and being
25 disposed outside the scroll casing,
an outside diameter of an end portion of the motor is formed to be larger than a
blade inside diameter of the plurality of blades beside the backing plate and smaller
than a blade inside diameter of the plurality of blades beside the rim.
[Claim 17]
30 An air-conditioning apparatus comprising the multi-blade air-sending device of
67
any one of claims 10 to 16.