FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
CENTRIFUGAL 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
CENTRIFUGAL AIR-SENDING DEVICE AND AIR-CONDITIONING APPARATUS
5 Technical Field
[0001]
The present disclosure relates to a centrifugal air-sending device that includes
an impeller and an air-conditioning apparatus that includes the centrifugal air-sending
device.
10 Background Art
[0002]
There has been a centrifugal air-sending device that has a scroll casing that is
scroll-shaped and has a bell mouth formed at an air inlet and an impeller that is
installed in the scroll casing and is configured to rotate about an axial center (refer to,
15 for example, Patent Literature 1). The impeller disclosed in Patent Literature 1 and
included in the centrifugal air-sending device has a main plate that is disk-shaped, a
side plate that is ring-shaped, and blades radially arranged. The blades included in
this impeller are arranged such that their inner diameter increases from the main plate
toward the side plate. The blades also are sirocco vanes, which are forward-curved
20 blades, and that each have a blade outlet angle of greater than or equal to 100
degrees and have inducer portions of turbo vanes, which are backward-curved blades,
at an inner circumference of the blades.
Citation List
Patent Literature
25 [0003]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2000-240590
Summary of Invention
Technical Problem
30 [0004]
3
In a case in which an impeller is resin-molded, to prevent its side plate from
sticking to a mold, such a side plate has been ring-shaped and provided to outer
circumferential side face of the impeller. In a centrifugal air-sending device that has
an impeller that has such a configuration, an airflow blown in a radial direction of the
5 impeller may pass outward around the side plate as its center and along an inner side
surface of a bell mouth and flow into the impeller again. In the centrifugal airsending device disclosed in Patent Literature 1, portions of blades that are located
further outward than an inner circumferential side end portion of the bell mouth are
formed only by portions formed as sirocco vane portions. When an airflow blown out
10 from the impeller and along an inner wall surface of the bell mouth flows into the
impeller again, the airflow thus collides with the sirocco vane portions, which each
have a large outlet angle and at which the airflow passes at increased inflow velocity.
Noise generated from the centrifugal air-sending device may be thus caused and
deterioration in input may be caused as well.
15 [0005]
The present disclosure is to solve the above problem and to provide a
centrifugal air-sending device, in which, when an airflow that passes along the inner
wall surface of the bell mouth passes into the impeller again, noise generated from
the airflow and deterioration in input are prevented, and an air-conditioning apparatus
20 that includes the centrifugal air-sending device.
Solution to Problem
[0006]
A centrifugal air-sending device according to an embodiment of the present
disclosure has an impeller that has a main plate that is to be driven to rotate, a side
25 plate that is ring-shaped and located such that the side plate faces the main plate,
and a plurality of blades that each have one end connected to the main plate and an
other end connected to the side plate and are arranged in a circumferential direction
centered on a rotation axis of the main plate that is virtual; and a scroll casing that
houses the impeller and has a circumferential wall that is scroll-shaped and a side
30 wall that has a bell mouth that forms a suction port that communicates with a space
4
defined by the main plate and the plurality of blades, in which the plurality of blades
each have an inner circumferential end that is closer to the rotation axis than is an
outer circumferential end in a radial direction centered on the rotation axis, the outer
circumferential end that is closer to an outer circumference than is the inner
5 circumferential end in the radial direction, a sirocco vane portion that includes the
outer circumferential end and forms a forward-curved blade at which an outlet angle
is formed larger than 90 degrees, a turbo vane portion that includes the inner
circumferential end and forms a backward-curved blade, a first region that is located
closer to the main plate than is an intermediate position between the main plate and
10 the side plate in an axial direction of the rotation axis, and a second region that is
located closer to the side plate than is the first region, the plurality of blades each
have a vane length in the first region that is greater than a vane length in the second
region, the plurality of blades are each formed such that a proportion for which the
turbo vane portion accounts is higher in the radial direction than a proportion for
15 which the sirocco vane portion accounts in the first region and the second region, and,
in a case in which portions of the plurality of blades that are located closer to the
outer circumference than is a blade inner diameter of the respective inner
circumferential ends of the plurality of blades at end portions of the plurality of blades
that are close to the side plate in the axial direction are defined as a blade outer
20 circumferential portion, the blade outer circumferential portion is formed such that a
vane thickness of each of the plurality of blades is decreased in the radial direction
from an inner circumference toward the outer circumference.
[0007]
An air-conditioning apparatus according to another embodiment of the present
25 disclosure has the centrifugal air-sending device, which has a configuration described
above.
Advantageous Effects of Invention
[0008]
According to an embodiment of the present disclosure, the blade outer
30 circumferential portion of the centrifugal air-sending device is formed such that the
5
vane thickness of each of the plurality of blades is decreased in the radial direction
from the inner circumference toward the outer circumference. In the centrifugal airsending device, vane intervals in the impeller are thus each gradually increased and
an opening area of each of the vane intervals is also increased toward discharge
5 ports of the blades. The centrifugal air-sending device that has the configuration
described above is configured to further reduce rapid pressure fluctuation when air is
blown out from the impeller and increase the amount of air blown out from the
impeller in comparison with a centrifugal air-sending device that does not have the
configuration described above. As a result, much air blown out from the impeller in
10 the centrifugal air-sending device that has the configuration described above passes
along an inner wall surface of the bell mouth into a portion of the impeller that is at the
inner circumference and collides with the turbo vane portions, which each have a
small outlet angle and at which an airflow passes at decreased inflow velocity. In the
centrifugal air-sending device, when the airflow that passes along the inner wall
15 surface of the bell mouth passes into the impeller again, since the airflow collides with
the turbo vane portions, which each have a small outlet angle and at which the airflow
passes at decreased inflow velocity, noise generated from the airflow is prevented
and deterioration in input is prevented as well.
Brief Description of Drawings
20 [0009]
[Fig. 1] Fig. 1 is a perspective view that schematically illustrates a centrifugal
air-sending device according to Embodiment 1.
[Fig. 2] Fig. 2 is an external view that schematically illustrates a configuration of
the centrifugal air-sending device according to Embodiment 1 with the configuration
25 viewed parallel to a rotation axis.
[Fig. 3] Fig. 3 is a sectional view that schematically illustrates a section of the
centrifugal air-sending device illustrated in Fig. 2 taken along line A-A.
[Fig. 4] Fig. 4 is a perspective view that illustrates an impeller included in the
centrifugal air-sending device according to Embodiment 1.
30 [Fig. 5] Fig. 5 is a perspective view that illustrates the impeller illustrated in Fig.
6
4 with the impeller viewed opposite to the perspective view illustrated in Fig. 4.
[Fig. 6] Fig. 6 is a plan view that illustrates the impeller included in the
centrifugal air-sending device according to Embodiment 1 with the impeller viewed
toward one face of the main plate.
5 [Fig. 7] Fig. 7 is a plan view that illustrates the impeller included in the
centrifugal air-sending device according to Embodiment 1 with the impeller viewed
toward the other face of the main plate.
[Fig. 8] Fig. 8 is a sectional view that illustrates the impeller illustrated in Fig. 6
taken along line B-B.
10 [Fig. 9] Fig. 9 is a side view that illustrates the impeller illustrated in Fig. 4.
[Fig. 10] Fig. 10 is a schematic view that illustrates a section of blades included
in the impeller illustrated in Fig. 9 taken along line C-C.
[Fig. 11] Fig. 11 is a schematic view that illustrates a section of the blades
included in the impeller illustrated in Fig. 9 taken along line D-D.
15 [Fig. 12] Fig. 12 is an enlarged view that illustrates a portion of the impeller that
is in range E in the impeller illustrated in Fig. 6.
[Fig. 13] Fig. 13 is a schematic view that illustrates a relationship between the
impeller and a scroll casing included in the centrifugal air-sending device illustrated in
Fig. 2 with the centrifugal air-sending device viewed in the section taken along line A20 A.
[Fig. 14] Fig. 14 is a schematic view that illustrates a relationship between the
blades and a bell mouth with the impeller illustrated in Fig. 13 viewed parallel to the
rotation axis.
[Fig. 15] Fig. 15 is a schematic view that further illustrates in detail the
25 relationship between the impeller and the scroll casing included in the centrifugal airsending device illustrated in Fig. 2 with the centrifugal air-sending device viewed in
the section taken along line A-A.
[Fig. 16] Fig. 16 is a schematic view that illustrates the relationship between the
blades and the bell mouth with the impeller illustrated in Fig. 15 viewed parallel to the
30 rotation axis.
7
[Fig. 17] Fig. 17 is a schematic view that illustrates the relationship between the
impeller and the scroll casing included in the centrifugal air-sending device illustrated
in Fig. 2 with the centrifugal air-sending device viewed in the section taken along line
A-A.
5 [Fig. 18] Fig. 18 is a schematic view that illustrates the relationship between the
blades and the bell mouth with the impeller illustrated in Fig. 17 viewed in a second
section and viewed parallel to the rotation axis.
[Fig. 19] Fig. 19 is a sectional view that illustrates a centrifugal air-sending
device according to a comparative example.
10 [Fig. 20] Fig. 20 is a sectional view that illustrates a portion of an impeller
included in a centrifugal air-sending device according to Embodiment 2 that is in
range E in the impeller illustrated in Fig. 6.
[Fig. 21] Fig. 21 is a conceptual view that illustrates a relationship between an
impeller and a bell mouth included in a centrifugal air-sending device according to
15 Embodiment 3.
[Fig. 22] Fig. 22 is a sectional view that schematically illustrates a centrifugal
air-sending device according to Embodiment 4.
[Fig. 23] Fig. 23 is an enlarged view that illustrates a portion of the impeller
included in the centrifugal air-sending device according to Embodiment 4 that is in
20 range E in the impeller illustrated in Fig. 6.
[Fig. 24] Fig. 24 is a sectional view that schematically illustrates a centrifugal
air-sending device according to Embodiment 5.
[Fig. 25] Fig. 25 is an enlarged view that illustrates a portion of the impeller
included in the centrifugal air-sending device according to Embodiment 5 that is in
25 range E in the impeller illustrated in Fig. 6.
[Fig. 26] Fig. 26 is a perspective view that illustrates an example of an airconditioning apparatus according to Embodiment 6.
[Fig. 27] Fig. 27 is a perspective view that illustrates an example of an internal
configuration of the air-conditioning apparatus according to Embodiment 6.
30 [Fig. 28] Fig. 28 is a side view that conceptualistically illustrates an example of
8
an internal configuration of the air-conditioning apparatus according to Embodiment 6.
[Fig. 29] Fig. 29 is a sectional view that illustrates a section of the centrifugal
air-sending device illustrated in Fig. 28 taken along line F-F.
[Fig. 30] Fig. 30 is a side view that conceptualistically illustrates an example of
5 an internal configuration of an air-conditioning apparatus according to Embodiment 7.
Description of Embodiment
[0010]
A centrifugal air-sending device and an air-conditioning apparatus according to
embodiments are described below with reference to the drawings and other reference.
10 In the drawings below, which include Fig. 1, the relative dimensions, shapes, and
other details of various components may differ from those of the actual components.
In addition, components given the same reference signs in the following drawings are
the same as or equivalent to each other, and these reference signs are common
through the full text of the specification. In addition, the directional terms, such as
15 “upper”, “lower”, “right”, “left”, “front”, and “back”, used as appropriate for ease of
comprehension are merely so written for convenience of explanation, and the
placement or orientation of a device or a component is not limited by the directional
terms.
[0011]
20 Embodiment 1
[Centrifugal Air-sending Device 100]
Fig. 1 is a perspective view that schematically illustrates a centrifugal airsending device 100 according to Embodiment 1. Fig. 2 is an external view that
schematically illustrates a configuration of the centrifugal air-sending device 100
25 according to Embodiment 1 with the configuration viewed parallel to a rotation axis
RS. Fig. 3 is a sectional view that schematically illustrates a section of the
centrifugal air-sending device 100 illustrated in Fig. 2 taken along line A-A. A basic
structure of the centrifugal air-sending device 100 is described below with reference
to Fig. 1 to Fig. 3.
30 [0012]
9
The centrifugal air-sending device 100 is a multi-blade air-sending device and
has an impeller 10 configured to generate an airflow and a scroll casing 40, which
houses the impeller 10. The centrifugal air-sending device 100 is also a doublesuction centrifugal air-sending device through which air is sucked from both sides of
5 the scroll casing 40 in an axial direction of the rotation axis RS, which is virtual, of the
impeller 10.
[0013]
[Scroll Casing 40]
The scroll casing 40 houses the impeller 10 for the centrifugal air-sending
10 device 100 and rectifies 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
The scroll portion 41 forms an air passage through which a dynamic pressure
15 of an airflow generated by the impeller 10 is converted into a static pressure. The
scroll portion 41 has side walls 44a that each cover the impeller 10 in the axial
direction of the rotation axis RS of the boss portion 11b included in the impeller 10
and each have a suction port 45 formed in the side wall 44a and through which air is
sucked and a circumferential wall 44c that surrounds the impeller 10 in radial
20 directions from the rotation axis RS of the boss portion 11b.
[0015]
In addition, the scroll portion 41 has a tongue portion 43, located between a
discharge portion 42 and a scroll start portion 41a of the circumferential wall 44c, that
has a curved surface and guides an airflow generated by the impeller 10 toward a
25 discharge port 42a through the scroll portion 41. The radial directions from the
rotation axis RS are each a direction perpendicular to the rotation axis RS. The
scroll portion 41 has an internal space, defined by the circumferential wall 44c and the
side walls 44a, in which air blown out from the impeller 10 flows along the
circumferential wall 44c.
30 [0016]
10
Side Walls 44a
The side walls 44a are located at both respective faces of the impeller 10 in the
axial direction of the rotation axis RS of the impeller 10. The side walls 44a of the
scroll casing 40 each have the suction port 45 formed in the side wall 44a such that
5 air is allowed to flow between the impeller 10 and an outside of the scroll casing 40.
[0017]
The suction port 45 is formed in a circular shape and the impeller 10 is located
such that the center of the suction port 45 and the center of the boss portion 11b of
the impeller 10 substantially coincide with each other. The shape of the suction port
10 45 is not limited to the circular shape and may also be another shape, such as an
elliptical shape.
[0018]
The scroll casing 40 of the centrifugal air-sending device 100 is a doublesuction casing that has the side walls 44a, which have the respective suction ports 45
15 at both faces of the main plate 11 in the axial direction of the rotation axis RS of the
boss portion 11b.
[0019]
The centrifugal air-sending device 100 has the two side walls 44a in the scroll
casing 40. The two side walls 44a are formed such that the side walls 44a face each
20 other across the circumferential wall 44c. More specifically, as illustrated in Fig. 3,
the scroll casing 40 has a first side wall 44a1 and a second side wall 44a2 as the side
walls 44a.
[0020]
The first side wall 44a1 has a first suction port 45a formed in the first side wall
25 44a1. The first suction port 45a faces a plate surface of the main plate 11 on which
a first side plate 13a, which is described later, is located. The second side wall 44a2
has a second suction port 45b formed in the second side wall 44a2. The second
suction port 45b faces a plate surface of the main plate 11 on which a second side
plate 13b, which is described later, is located. The first suction port 45a and the
30 second suction port 45b are collectively referred to as the suction ports 45 described
11
above.
[0021]
The suction port 45 located in the side wall 44a is formed by a bell mouth 46.
The bell mouth 46 forms the suction port 45, which communicates with a space
5 defined by the main plate 11 and a plurality of blades 12. The bell mouth 46 rectifies
a flow of gas to be sucked into the impeller 10 and causes the gas to flow into the air
inlet 10e of the impeller 10.
[0022]
The bell mouth 46 has an opening of which a diameter gradually decreases
10 from the outside toward the inside of the scroll casing 40. Such a configuration of
each of the side walls 44a allows air around the suction ports 45 to smoothly flow
along the bell mouths 46 and efficiently flow from the suction ports 45 into the impeller
10.
[0023]
15 Circumferential Wall 44c
The circumferential wall 44c is a wall that has a curved wall surface along
which an airflow generated by the impeller 10 is guided toward the discharge port 42a.
The circumferential wall 44c is located between the side walls 44a, which face each
other, and forms a curved surface that extends along the rotation direction R of the
20 impeller 10. The circumferential wall 44c is located, for example, parallel to the axial
direction of the rotation axis RS of the impeller 10 and covers the impeller 10. The
circumferential wall 44c may also be shaped such that the circumferential wall 44c is
inclined to the axial direction of the rotation axis RS in the impeller 10 and is not
limited to be located parallel to the axial direction of the rotation axis RS.
25 [0024]
The circumferential wall 44c has an inner circumferential surface that covers
the impeller 10 in the radial directions of the boss portion 11b and faces the plurality
of blades 12, which are described later. The circumferential wall 44c faces air
outlets of the blades 12 in the impeller 10. As illustrated in Fig. 2, the circumferential
30 wall 44c is located over an area from the scroll start portion 41a located at a boundary

We Claim :
[Claim 1]
A centrifugal air-sending device comprising:
an impeller that has a main plate that is to be driven to rotate, a side plate that
5 is ring-shaped and located such that the side plate faces the main plate, and a
plurality of blades that each have one end connected to the main plate and an other
end connected to the side plate and are arranged in a circumferential direction
centered on a rotation axis of the main plate that is virtual; and
a scroll casing that houses the impeller and has a circumferential wall that is
10 scroll-shaped and a side wall that has a bell mouth that forms a suction port that
communicates with a space defined by the main plate and the plurality of blades,
the plurality of blades each having
an inner circumferential end that is closer to the rotation axis than is an outer
circumferential end in a radial direction centered on the rotation axis,
15 the outer circumferential end that is closer to an outer circumference than is the
inner circumferential end in the radial direction,
a sirocco vane portion that includes the outer circumferential end and forms a
forward-curved blade at which an outlet angle is formed larger than 90 degrees,
a turbo vane portion that includes the inner circumferential end and forms a
20 backward-curved blade,
a first region that is located closer to the main plate than is an intermediate
position between the main plate and the side plate in an axial direction of the rotation
axis, and
a second region that is located closer to the side plate than is the first region,
25 the plurality of blades each having a vane length in the first region that is
greater than a vane length in the second region,
the plurality of blades being each formed such that a proportion for which the
turbo vane portion accounts is higher in the radial direction than a proportion for
which the sirocco vane portion accounts in the first region and the second region,
30 in a case in which portions of the plurality of blades that are located closer to
65
the outer circumference than is a blade inner diameter of the respective inner
circumferential ends of the plurality of blades at end portions of the plurality of blades
that are close to the side plate in the axial direction are defined as a blade outer
circumferential portion, the blade outer circumferential portion is formed such that a
5 vane thickness of each of the plurality of blades is decreased in the radial direction
from an inner circumference toward the outer circumference.
[Claim 2]
The centrifugal air-sending device of claim 1, wherein the centrifugal airsending device is formed such that the vane thickness at each of only the sirocco
10 vane portions of the plurality of blades is decreased in the radial direction from the
inner circumference toward the outer circumference.
[Claim 3]
The centrifugal air-sending device of claim 1 or 2, wherein the plurality of
blades are formed such that the vane thickness at each of the turbo vane portions of
15 the plurality of blades is constant in each section in the axial direction from the inner
circumference toward the outer circumference of the impeller.
[Claim 4]
The centrifugal air-sending device of any one of claims 1 to 3, wherein the
plurality of blades are each formed such that the turbo vane portion and the sirocco
20 vane portion are separated from each other in the radial direction.
[Claim 5]
The centrifugal air-sending device of any one of claims 1 to 4, wherein
the plurality of blades are each formed such that a blade outer diameter of the
respective outer circumferential ends of the plurality of blades is larger than an inner
25 diameter of the bell mouth, and,
in a case in which portions of the plurality of blades that are located closer to
the outer circumference than is an inner circumferential side end portion that is an
end portion of the bell mouth that is located closest to the inner circumference in the
radial direction are defined as an outer circumferential region portion,
30 the outer circumferential region portion is formed such that the proportion for
66
which the sirocco vane portion accounts is higher in the radial direction than the
proportion for which the turbo vane portion accounts in the first region and the second
region.
[Claim 6]
5 An air-conditioning apparatus comprising the centrifugal air-sending device of
any one of claims 1 to 5.
[Claim 7]
An air-conditioning apparatus, comprising:
the centrifugal air-sending device of any one of claims 1 to 5;
10 a heat exchanger located such that the heat exchanger faces the centrifugal
air-sending device; and
a housing that houses the centrifugal air-sending device and the heat
exchanger and in which a housing inlet port through which air that is to be sucked into
the centrifugal air-sending device flows is formed and a housing outlet port through
15 which air that is discharged from the centrifugal air-sending device and has passed
through the heat exchanger flows is formed, wherein
the scroll casing has a tongue portion that separates an airflow blown out from
the impeller, and,
in a case in which the centrifugal air-sending device is viewed in the axial
20 direction of the rotation axis, a portion divided by the rotation axis and in which the
tongue portion is located is defined as a tongue-portion including section and a
portion divided by the rotation axis and located closer to the housing inlet port than is
the tongue-portion including section is defined as an inlet-port facing section, and a
distance between an inner circumferential edge portion and an outer circumferential
25 edge portion of the bell mouth in the radial direction in the tongue-portion including
section is defined as a first distance and a distance between the inner circumferential
edge portion and the outer circumferential edge portion of the bell mouth in the radial
direction in the inlet-port facing section is defined as a second distance, the scroll
casing is formed such that the first distance is smaller than the second distance.
30 [Claim 8]
67
The air-conditioning apparatus of claim 7, wherein,
in a direction in which air flows between the impeller and the circumferential
wall, a ratio at which a distance between the impeller and the circumferential wall is
increased from an upstream portion toward a downstream portion is defined as a
5 scroll enlargement ratio, the scroll enlargement ratio at a portion of the scroll casing in
the tongue-portion including section is defined as a first enlargement ratio, and the
scroll enlargement ratio at a portion of the scroll casing in the inlet-port facing section
is defined as a second enlargement ratio,
the scroll casing is formed such that the second enlargement ratio is higher
10 than the first enlargement ratio.
[Claim 9]
An air-conditioning apparatus, comprising:
the centrifugal air-sending device of any one of claims 1 to 5;
a heat exchanger located such that the heat exchanger faces the centrifugal
15 air-sending device; and
a housing that houses the centrifugal air-sending device and the heat
exchanger and in which a housing inlet port through which air that is to be sucked into
the centrifugal air-sending device flows is formed and a housing outlet port through
which air that is discharged from the centrifugal air-sending device and has passed
20 through the heat exchanger flows is formed, wherein
the scroll casing has a tongue portion that separates an airflow blown out from
the impeller, and,
in a case in which the centrifugal air-sending device is viewed in the axial
direction of the rotation axis, a portion divided by the rotation axis and in which the
25 tongue portion is located is defined as a tongue-portion including section and a
portion divided by the rotation axis and located closer to the housing inlet port than is
the tongue-portion including section is defined as an inlet-port facing section, and, in
a direction in which air flows between the impeller and the circumferential wall, a ratio
at which a distance between the impeller and the circumferential wall is increased
30 from an upstream portion toward a downstream portion is defined as a scroll
68
enlargement ratio, the scroll enlargement ratio at a portion of the scroll casing in the
tongue-portion including section is defined as a first enlargement ratio, and the scroll
enlargement ratio at a portion of the scroll casing in the inlet-port facing section is
defined as a second enlargement ratio,
5 the scroll casing is formed such that the second enlargement ratio is higher
than the first enlargement ratio.