U.S. patent application number 16/494956 was filed with the patent office on 2020-08-27 for propeller-shaped impeller and railway carriage air-conditioning apparatus.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Hiroaki MURAKAMI, Seiji NAKASHIMA, Wahei SHINGU.
Application Number | 20200269885 16/494956 |
Document ID | / |
Family ID | 1000004840988 |
Filed Date | 2020-08-27 |
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United States Patent
Application |
20200269885 |
Kind Code |
A1 |
MURAKAMI; Hiroaki ; et
al. |
August 27, 2020 |
PROPELLER-SHAPED IMPELLER AND RAILWAY CARRIAGE AIR-CONDITIONING
APPARATUS
Abstract
A boss fitted to a rotation shaft of a motor is placed on a
bearing surface. An airflow producing unit includes blades
protruding from the boss in a radial direction of the shaft and
rotating with the boss. The boss includes a first end surface to
contact the bearing surface when fitted to the shaft with a first
end of the boss in a thickness direction facing the bearing
surface, and a second end surface to contact the bearing surface
when fitted to the shaft with a second end of the boss in the
thickness direction facing the bearing surface. A degree of
symmetry defined by A/B falls within a range of 1.0 to 1.3, where A
is a height of the airflow producing unit from the first end
surface, B is a height of the airflow producing unit from the
second end surface, and A B.
Inventors: |
MURAKAMI; Hiroaki; (Tokyo,
JP) ; SHINGU; Wahei; (Tokyo, JP) ; NAKASHIMA;
Seiji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Chiyoda-ku, Tokyo |
|
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Chiyoda-ku, Tokyo
JP
|
Family ID: |
1000004840988 |
Appl. No.: |
16/494956 |
Filed: |
May 21, 2018 |
PCT Filed: |
May 21, 2018 |
PCT NO: |
PCT/JP2018/019502 |
371 Date: |
September 17, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61D 27/0018 20130101;
B60H 1/00371 20130101; F04D 29/384 20130101; F24F 1/50 20130101;
B60H 2001/00235 20130101; F04D 29/36 20130101 |
International
Class: |
B61D 27/00 20060101
B61D027/00; F04D 29/38 20060101 F04D029/38 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2017 |
JP |
2017-107436 |
Claims
1. A propeller-shaped impeller, comprising: a boss rotatable with a
rotation shaft of a motor having a bearing surface from which the
rotation shaft protrudes, the boss being configured to be placed on
the bearing surface as being fitted to the rotation shaft of the
motor; and an airflow producing unit including a plurality of
blades protruding from the boss outwardly in a radial direction of
the rotation shaft and rotatable together with the boss to produce
an airflow, wherein the boss includes a first end surface
configured to come in contact with the bearing surface when the
boss is fitted to the rotation shaft with one end of the boss in a
thickness direction parallel to the rotation shaft facing the
bearing surface, and a second end surface configured to come in
contact with the bearing surface when the boss is fitted to the
rotation shaft with another end of the boss in the thickness
direction facing the bearing surface, and a degree of symmetry
defined by A/B falls within a range of 1.0 to 1.3 inclusive, where
A is a height of the airflow producing unit from one end surface of
the first end surface and the second end surface, B is a height of
the airflow producing unit from another end surface of the first
end surface and the second end surface, and A B.
2. The propeller-shaped impeller according to claim 1, wherein a
sum of the height A of the airflow producing unit from the one end
surface and the height B of the airflow producing unit from the
another end surface is not greater than 115 mm, and the airflow
producing unit has a forward inclination angle.
3. The propeller-shaped impeller according to claim 1, wherein a
sum of the height A of the airflow producing unit from the one end
surface and the height B of the airflow producing unit from the
another end surface is not greater than 115 mm, and the airflow
producing unit has a stagger angle of not greater than
75.degree..
4. The propeller-shaped impeller according to claim 1, wherein a
sum of the height A of the airflow producing unit from the one end
surface and the height B of the airflow producing unit from the
another end surface exceeds 115 mm, and the airflow producing unit
has a cutout to avoid contact with the motor.
5. The propeller-shaped impeller according to claim 1, wherein an
aspect ratio defined by C/D falls within a range of 0.10 to 0.16
inclusive, where C is a total height of the airflow producing unit
and D is a diameter of the airflow producing unit.
6. A railway carriage air-conditioning apparatus, comprising: an
outdoor heat exchanger having a structure to allow refrigerant to
flow inside and configured to exchange heat with air; an outdoor
blower including the propeller-shaped impeller according to claim
1, and the motor to which the propeller-shaped impeller is
attached, and configured to take in air from outside a railway
carriage, cause the air to pass through the outdoor heat exchanger,
and discharge the air out of the railway carriage; and a
collaborative system to provide a refrigerating cycle together with
the outdoor heat exchanger using the refrigerant.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a propeller-shaped
impeller and a railway carriage air-conditioning apparatus.
BACKGROUND ART
[0002] A railway carriage air-conditioning apparatus for
air-conditioning a railway carriage cabin includes an outdoor unit
accommodated in an outdoor-unit chamber on the ceiling of a railway
carriage. The outdoor unit includes an outdoor heat exchanger that
exchanges heat with air that passes through the exchanger, and an
outdoor blower that produces an airflow passing through the
exchanger. The outdoor blower includes a propeller-shaped impeller
and a motor that rotates the impeller.
[0003] Patent Literature 1 describes an outdoor blower that draws
air into an outdoor-unit chamber through the sides of the
outdoor-unit chamber, allows the drawn air to pass through the
outdoor heat exchanger, and then discharges the air above the
outdoor-unit chamber. The operation of the outdoor blower that
produces such an airflow will be hereafter referred to as upward
blowing.
[0004] Patent Literature 2 describes an outdoor blower that draws
air into an outdoor-unit chamber from above the outdoor-unit
chamber, allows the drawn air to pass through the outdoor heat
exchanger, and then discharges the air to the sides of the
outdoor-unit chamber, in contrast to the outdoor blower described
in Patent Literature 1. The operation of the outdoor blower that
produces such an airflow will be hereafter referred to as downward
blowing.
CITATION LIST
Patent Literature
[0005] Patent Literature 1: Unexamined Japanese Patent Application
Kokai Publication No. 2006-273099 [0006] Patent Literature 2:
Unexamined Japanese Patent Application Kokai Publication No.
2003-48536
SUMMARY OF INVENTION
Technical Problem
[0007] If the propeller-shaped impeller can be attached to the
motor upside down, the outdoor blower described in Patent
Literature 1 can blow air downward, as in the outdoor blower
according to Patent Literature 2. If the propeller-shaped impeller
can be attached to the motor upside down, the outdoor blower
described in Patent Literature 2 can blow air upward, as in the
outdoor blower according to Patent Literature 1.
[0008] However, the propeller-shaped impeller turned upside down
can contact other components without an enough space in the
outdoor-unit chamber in the railway carriage. Thus, two different
propeller-shaped impellers with the same diameter are to be
prepared separately for upward blowing and downward blowing. To
reduce the variety of propeller-shaped impellers to be prepared, a
propeller-shaped impeller usable for both upward blowing and
downward blowing has been awaited.
[0009] One or more aspects of the present disclosure are directed
to a propeller-shaped impeller usable upside down less likely to
contact other components, and a railway carriage air-conditioning
apparatus including the impeller.
Solution to Problem
[0010] In response to the above issue, a propeller-shaped impeller
according to an aspect of the present disclosure includes a boss
rotatable with a rotation shaft of a motor having a bearing surface
from which the rotation shaft protrudes, the boss being configured
to be placed on the bearing surface as being fitted to the rotation
shaft of the motor, and an airflow producing unit including a
plurality of blades protruding from the boss outwardly in a radial
direction of the rotation shaft and rotatable together with the
boss to produce an airflow. The boss includes a first end surface
to come in contact with the bearing surface when the boss is fitted
to the rotation shaft with one end of the boss in a thickness
direction parallel to the rotation shaft facing the bearing
surface, and a second end surface to come in contact with the
bearing surface when the boss is fitted to the rotation shaft with
another end of the boss in the thickness direction facing the
bearing surface, and a degree of symmetry defined by A/B falls
within a range of 1.0 to 1.3 inclusive, where A is a height of the
airflow producing unit from one end surface of the first end
surface and the second end surface, B is a height of the airflow
producing unit from another end surface of the first end surface
and the second end surface, and A.gtoreq.B.
Advantageous Effects of Invention
[0011] The propeller-shaped impeller according to one or more
aspects of the present disclosure has the degree of symmetry within
the range of 1.0 to 1.3 inclusive, and is thus less likely to
contact other components when used upside down.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1A is a partial cross-sectional view of an outdoor-unit
chamber accommodating an outdoor blower according to Embodiment 1
blowing air upward, taken along line AA-AA in FIG. 8A;
[0013] FIG. 1B is a partial cross-sectional view of the
outdoor-unit chamber accommodating the outdoor blower according to
Embodiment 1 blowing air downward, taken along line AA-AA;
[0014] FIG. 2 is a side view of the outdoor blower according to
Embodiment 1;
[0015] FIG. 3A is a side view of an outdoor blower according to
Embodiment 2;
[0016] FIG. 3B is a plan view of a part of the outdoor blower
according to Embodiment 2;
[0017] FIG. 4A is a side view of a part of an outdoor blower
according to Embodiment 3;
[0018] FIG. 4B is a cross-sectional view of a blade of the outdoor
blower according to Embodiment 3;
[0019] FIG. 5 is a side view of an outdoor blower according to
Embodiment 4;
[0020] FIG. 6A is a partial cross-sectional view of an outdoor-unit
chamber accommodating an outdoor blower according to a comparative
example blowing air upward, taken along line AA-AA;
[0021] FIG. 6B is a partial cross-sectional view of the
outdoor-unit chamber accommodating the outdoor blower according to
the comparative example blowing air downward, taken along line
AA-AA;
[0022] FIG. 7 is a partial cross-sectional plan view of an inside
of an outdoor-unit chamber of a railway carriage air-conditioning
apparatus according to Embodiment 1;
[0023] FIG. 8A is a plan view of the railway carriage
air-conditioning apparatus according to Embodiment 1; and
[0024] FIG. 8B is a functional block diagram of an air-conditioning
apparatus according to Embodiment 1.
DESCRIPTION OF EMBODIMENTS
[0025] A railway carriage air-conditioning apparatus according to
one or more embodiments of the present disclosure will now be
described with reference to the drawings. Throughout the drawings,
the same or corresponding components are given the same reference
numerals.
Embodiment 1
[0026] The overall structure of a railway carriage air-conditioning
apparatus 100 according to the present embodiment will be described
with reference to FIGS. 8A and 8B. The railway carriage
air-conditioning apparatus 100 includes a housing 10 shown in FIG.
8A, and an air-conditioning apparatus 20 shown in FIG. 8B
accommodated in the housing 10.
[0027] The housing 10 shown in FIG. 8A includes a box-shaped base
frame 11 with an upper opening, a cover 12 that closes the upper
opening of the base frame 11, and a partition plate 13 that
partitions the interior space defined by the base frame 11 and the
cover 12. The partition plate 13 partitions the interior space of
the housing 10 into an outdoor-unit chamber R1 and an indoor-unit
chamber R2 in a direction in which a railway carriage travels.
[0028] The cover 12 has a first vent 121 and two second vents 122a
and 122b in an area that covers the outdoor-unit chamber R1. The
second vents 122a and 122b are each spaced apart from the first
vent 121. The outdoor-unit chamber R1 communicates with the outside
through the first vent 121 and the second vents 122a and 122b.
[0029] The first vent 121 is circular in a plan view. The second
vents 122a and 122b are rectangular in a plan view and are
elongated in the direction in which the railway carriage travels.
The two second vents 122a and 122b are spaced apart across the
first vent 121 in the width direction of the railway carriage.
[0030] The air-conditioning apparatus 20 shown in FIG. 8B provides
a refrigerating cycle using refrigerant to air-condition a railway
carriage chamber. The chamber herein refers to a space in the
railway carriage defined for passengers or staff, and is
specifically a cabin or an operator cab.
[0031] The air-conditioning apparatus 20 includes an outdoor heat
exchanger 21 that allows refrigerant to flow through the inside and
a collaborative system 22 that provides a refrigerating cycle
together with the outdoor heat exchanger 21 using the
refrigerant.
[0032] The function of the outdoor heat exchanger 21 and the
components and the function of the collaborative system 22 for
cooling a chamber will now be described below by way of example.
The outdoor heat exchanger 21 functions as a condenser that
exchanges heat between refrigerant and air to condense the
refrigerant.
[0033] The collaborative system 22 includes an expander 22a that
expands the refrigerant condensed by the outdoor heat exchanger 21,
an indoor heat exchanger 22b that functions as an evaporator for
vaporizing the expanded refrigerant, a vapor-liquid separator 22c
that separates a gaseous refrigerant from a liquid refrigerant, and
a compressor 22d that compresses the gaseous refrigerant. The
collaborative system 22 also includes a refrigerant pipe 22e that
connects the outdoor heat exchanger 21, the expander 22a, the
indoor heat exchanger 22b, the vapor-liquid separator 22c, and the
compressor 22d to one another to allow the refrigerant to flow
through these components.
[0034] The air-conditioning apparatus 20 includes an indoor blower
23 that facilitates heat exchange between the indoor heat exchanger
22b and air, and an outdoor blower 24 that facilitates heat
exchange between the outdoor heat exchanger 21 and air. The indoor
blower 23 includes a centrifugal blower. The outdoor blower 24
includes an axial-flow blower.
[0035] The indoor blower 23 feeds air that has exchanged heat with
the indoor heat exchanger 22b into the railway carriage chamber.
The outdoor blower 24 takes in air from outside the railway
carriage, allows the air to flow through the outdoor heat exchanger
21, and discharges the air out of the railway carriage.
[0036] Among the components of the air-conditioning apparatus 20
described above, the outdoor heat exchanger 21 and the outdoor
blower 24 are accommodated in the outdoor-unit chamber R1 shown in
FIG. 8A. The expander 22a, the indoor heat exchanger 22b, the
vapor-liquid separator 22c, the compressor 22d, and the indoor
blower 23 are accommodated in the indoor-unit chamber R2 shown in
FIG. 8A. The refrigerant pipe 22e extends through the partition
plate 13 across both the outdoor-unit chamber R1 and the
indoor-unit chamber R2.
[0037] The railway carriage air-conditioning apparatus 100
according to the present embodiment is characterized by the
internal structure of the outdoor-unit chamber R1. The internal
structure of the outdoor-unit chamber R1 will now be described
below in detail.
[0038] As shown in FIG. 7, the outdoor heat exchanger 21 includes a
first outdoor heat exchanger 21a and a second outdoor heat
exchanger 21b located across both sides of the outdoor blower 24 in
the width direction of the railway carriage in a plan view. The
outdoor blower 24 is thus located between the first and second
outdoor heat exchangers 21a and 21b.
[0039] As shown in FIG. 1A, the outdoor blower 24 is mounted on a
bottom surface 11a of the base frame 11. The cover 12 facing the
bottom surface 11a of the base frame 11 has a level portion in the
middle in the width direction of the railway carriage. The level
portion has the first vent 121 also shown in FIG. 8A. The cover 12
has, in the width direction of the railway carriage, two shoulder
portions that are inclined downward. The inclined portions of the
two shoulders have the second vents 122a and 122b also shown in
FIG. 8A.
[0040] The first outdoor heat exchanger 21a faces the second vent
122a. The second outdoor heat exchanger 21b faces the second vent
122b. The first and second outdoor heat exchangers 21a and 21b are
inclined downward along the inclinations of the two shoulders of
the cover 12.
[0041] The two shoulders of the cover 12 are inclined and the first
and second outdoor heat exchangers 21a and 21b are inclined along
the inclinations to achieve highly efficient heat exchange while
reducing the total height of the outdoor-unit chamber R1 or
specifically reducing the height of the base frame 11 from the
bottom surface 11a to the first vent 121.
[0042] The outdoor blower 24 includes a propeller-shaped impeller
30 for a railway carriage air-conditioning apparatus for producing
an airflow, and a motor 40 that rotates the propeller-shaped
impeller 30 for a railway carriage air-conditioning apparatus. The
motor 40 includes a rotation shaft 41 to which the propeller-shaped
impeller 30 for a railway carriage air-conditioning apparatus is
fitted. The rotation shaft 41 extends in a direction normal to the
bottom surface 11a of the base frame 11. The first vent 121 is
located above the propeller-shaped impeller 30 for a railway
carriage air-conditioning apparatus fitted to the rotation shaft
41.
[0043] A bellmouth 50 is located as the outer periphery of the
propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus to surround the propeller-shaped
impeller 30. The bellmouth 50 has a tube shape flared toward the
bottom surface 11a of the base frame 11.
[0044] When rotated by the motor 40, the propeller-shaped impeller
30 for a railway carriage air-conditioning apparatus forms an
airflow flowing from the second vents 122a and 122b to the first
vent 121 in the outdoor-unit chamber R1. The bellmouth 50 regulates
the airflow.
[0045] More specifically, the propeller-shaped impeller 30 forms an
airflow that flows into the outdoor-unit chamber R1 from the sides
of the outdoor-unit chamber R1 through the second vents 122a and
122b, passes through the first and second outdoor heat exchangers
21a and 21b, passes through the bellmouth 50, and flows out from
above the outdoor-unit chamber R1 through the first vent 121. This
operation of the outdoor blower 24 forming such an airflow will be
hereafter referred to as upward blowing.
[0046] FIG. 1B shows an airflow opposite to the airflow shown in
FIG. 1A, that is, an airflow that flows downward into the
outdoor-unit chamber R1 from above the outdoor-unit chamber R1,
passes through the bellmouth 50, passes through the first and
second outdoor heat exchangers 21a and 21b, and flows out from the
sides of the outdoor-unit chamber R1. This operation of the outdoor
blower 24 forming such an airflow will be hereafter referred to as
downward blowing. For downward blowing, the bellmouth 50 is
attached with the flared end facing the cover 12.
[0047] The propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus according to the present embodiment has
a shape usable for both upward blowing and downward blowing shown
in FIGS. 1A and 1B. To clarify the effects of the shape of the
propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus, a comparative example will be described
below with reference to FIGS. 6A and 6B.
[0048] As shown in FIG. 6A, a propeller-shaped impeller 90 for a
railway carriage air-conditioning apparatus according to the
comparative example also produces an airflow from the second vents
122a and 122b to the first vent 121. However, the propeller-shaped
impeller 90 for a railway carriage air-conditioning apparatus
cannot produce an airflow opposite to the airflow shown in FIG. 6A,
that is, an airflow from the first vent 121 to the second vents
122a and 122b. This will be described in detail below.
[0049] As shown in FIG. 6B, if attachable to the motor 40 upside
down or turned over, the propeller-shaped impeller 90 for a railway
carriage air-conditioning apparatus can produce an airflow from the
first vent 121 to the second vents 122a and 122b. However, when
turned upside down, the propeller-shaped impeller 90 for a railway
carriage air-conditioning apparatus has an upper end portion 91
contacting the cover 12. The propeller-shaped impeller 90 for a
railway carriage air-conditioning apparatus thus cannot produce an
airflow shown in FIG. 6B.
[0050] To produce an airflow shown in FIG. 6B, a propeller-shaped
impeller for a railway carriage air-conditioning apparatus that
does not contact the cover 12 is to be prepared separately. Two
different propeller-shaped impellers for railway carriage
air-conditioning apparatuses with the same diameter are thus to be
prepared separately for upward blowing and downward blowing. This
increases the variety of propeller-shaped impellers for railway
carriage air-conditioning apparatuses to be prepared.
[0051] FIG. 6B shows the propeller-shaped impeller 90 for a railway
carriage air-conditioning apparatus that contacts the cover 12 by
way of example. The part that contacts the propeller-shaped
impeller 90 for a railway carriage air-conditioning apparatus is
not limited to this example. For railway carriages, the
outdoor-unit chamber R1 tends to have a lower height, and thus
tends to have almost no excess interior space. This minimizes the
clearance between the propeller-shaped impeller 90 for a railway
carriage air-conditioning apparatus and the components surrounding
the propeller-shaped impeller 90 for a railway carriage
air-conditioning apparatus. If turned upside down, the
propeller-shaped impeller 90 for a railway carriage
air-conditioning apparatus can contact any components,
particularly, the motor 40.
[0052] Following the comparative example described above, the
present embodiment will be described again with reference to FIG.
2.
[0053] As shown in FIG. 2, the propeller-shaped impeller 30 for a
railway carriage air-conditioning apparatus according to the
present embodiment includes a boss 31 fitted to the rotation shaft
41 of the motor 40, and an airflow producing unit 32 that produces
an airflow by rotating together with the boss 31. As shown in FIG.
7, the airflow producing unit 32 includes multiple blades 321
protruding from the boss 31 outwardly in a radial direction of the
rotation shaft 41.
[0054] FIG. 2 is a projection view of the airflow producing unit 32
while rotating. FIG. 2 shows the airflow producing unit 32 in a
projection view in which the locus of rotation of each blade 321
shown in FIG. 7 is projected on a virtual plane including a
centerline of the rotation shaft 41. The same applies to FIGS. 3A
and 5 referred to later.
[0055] The motor 40 includes the rotation shaft 41 and a bearing
surface 42 that rotates together with the rotation shaft 41. The
rotation shaft 41 protrudes from the bearing surface 42. The boss
31 of the propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus is mounted on the bearing surface 42.
When the propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus is mounted on the bearing surface 42,
the inner periphery of the airflow producing unit 32 facing the
rotation shaft 41 is located inward from the outer peripheral
surface of the motor 40 in the radial direction of the rotation
shaft 41.
[0056] The boss 31 has a first end surface 31a that comes in
contact with the bearing surface 42 while having one end in a
thickness direction facing the bearing surface 42 and fitted to the
rotation shaft 41, and a second end surface 31b that comes in
contact with the bearing surface 42 while having the other end in
the thickness direction facing the bearing surface 42 and fitted to
the rotation shaft 41. FIG. 2 shows the second end surface 31b in
contact with the bearing surface 42. The thickness direction of the
boss 31 refers to a direction parallel to the rotation shaft 41 of
the boss 31.
[0057] The propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus according to the present embodiment has
a shape with a degree of symmetry of 1.0 defined by X/Y, where X is
the height of the airflow producing unit 32 from the first end
surface 31a, and Y is the height of the airflow producing unit 32
from the second end surface 31b. More specifically, X and Y are 50
mm.
[0058] The height of the airflow producing unit 32 from the first
end surface 31a herein refers to the height of the airflow
producing unit 32 from the first end surface 31a along the rotation
shaft 41 of the motor 40 in a direction from the second end surface
31b toward the first end surface 31a. The height of the airflow
producing unit 32 from the second end surface 31b herein refers to
the height of the airflow producing unit 32 from the second end
surface 31b along the rotation shaft 41 of the motor 40 in a
direction from the first end surface 31a toward the second end
surface 31b.
[0059] As shown in FIG. 1B, the propeller-shaped impeller 30 for a
railway carriage air-conditioning apparatus having the shape with
the degree of symmetry of 1.0 does not contact other components,
such as the cover 12 or the motor 40, when attached to the motor 40
upside down, that is, turned over from the state shown in FIG. 1A.
The propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus can thus blow air downward.
[0060] The propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus is thus widely usable for upward blowing
and downward blowing. This eliminates the need to prepare two
different propeller-shaped impellers for railway carriage
air-conditioning apparatuses separately for upward blowing and
downward blowing, and reduces the variety of propeller-shaped
impellers for railway carriage air-conditioning apparatuses.
[0061] In the present embodiment, X=Y. However, any structure
having a degree of symmetry defined by AB within the range of 1.0
to 1.3 inclusive has similar effects, where A is the height of the
airflow producing unit 32 from the first or second end surface 31a
or 31b, and B is the height of the airflow producing unit 32 from
the other end surface (where A.gtoreq.B) in FIG. 2. To further
reduce the likelihood of the upside-down propeller-shaped impeller
30 for a railway carriage air-conditioning apparatus contacting
other components, the degree of symmetry defined by A/B may be
lower than or equal to 1.2, and more specifically lower than or
equal to 1.1.
[0062] For railway carriages, the outdoor-unit chamber R1 tends to
have the lowest possible height. The propeller-shaped impeller 30
for a railway carriage air-conditioning apparatus used in a railway
carriage is thus flatter than impellers for other uses. More
specifically, the aspect ratio defined by C/D falls within the
range of 0.10 to 0.16 inclusive, where C is the total height of the
airflow producing unit 32, and D is the diameter of the airflow
producing unit 32 in FIG. 2.
[0063] The total height C of the airflow producing unit 32 refers
to the distance from an end point of the airflow producing unit 32
at the height A from the first end surface 31a to an end point of
the airflow producing unit 32 at the height B from the second end
surface 31b in a direction parallel to the rotation shaft 41. The
diameter D of the airflow producing unit 32 refers to the diameter
of a virtual circle representing the locus of the end point of the
airflow producing unit 32 farthest from the rotation shaft 41 in
the radial direction of the rotation shaft 41.
[0064] The airflow producing unit 32 having the aspect ratio
defined by C/D lower than or equal to 0.16 has a large space E
between the airflow producing unit 32 and the bottom surface 11a
that serves as a mount surface for receiving the motor 40. In other
words, the airflow producing unit 32 has a sufficiently wide flow
path for an airflow produced by the airflow producing unit 32, and
thus reduces a pressure loss. The airflow producing unit 32 having
the aspect ratio defined by C/D higher than or equal to 0.10 is
less likely to be too flat to degrade the capability of taking in
air.
Embodiment 2
[0065] FIG. 2 shows the airflow producing unit 32 having a forward
inclination angle of 0.degree. indicating the inclination of the
airflow producing unit 32 with respect to a virtual plane parallel
to the first and second end surfaces 31a and 31b. The airflow
producing unit 32 is sufficiently flat when the sum of A+B is lower
than or equal to 115 mm, or more specifically, when the height A
falls within the range of 1 to 65 mm inclusive and the height B
falls within the range of 1 to 50 mm inclusive. Thus, with the
airflow producing unit 32 having a forward inclination angle, the
propeller-shaped impeller 30 for a railway carriage
air-conditioning apparatus is less likely to contact other
components when turned over. Specific examples of a
propeller-shaped impeller for a railway carriage air-conditioning
apparatus with an airflow producing unit having a forward
inclination angle will be described below.
[0066] As shown in FIG. 3A, a propeller-shaped impeller 60 for a
railway carriage air-conditioning apparatus according to the
present embodiment includes a boss 61 and an airflow producing unit
62 protruding from the boss 61 as in Embodiment 1, but differs in
that the airflow producing unit 62 has a forward inclination angle
.alpha..
[0067] In the present embodiment, the forward inclination angle
.alpha. is not greater than 40.degree.. The propeller-shaped
impeller 60 for a railway carriage air-conditioning apparatus can
be turned over when attached and is thus usable for both upward
blowing and downward blowing. When the propeller-shaped impeller 60
is turned over, the sign indicating the forward inclination angle
is inversed. The forward inclination angle herein is thus expressed
in an absolute value. In other words, the forward inclination angle
refers to the forward inclination angle expressed in an absolute
value exceeding 0.degree..
[0068] The forward inclination angle .alpha. will be described with
reference to FIG. 3B. As shown in FIG. 3B, a blade centerline CL is
defined with the locus of a middle point of a chord of a blade 621
included in the airflow producing unit 62. As shown in FIG. 3A, the
forward inclination angle .alpha. refers to an angle formed by the
blade centerline CL and a virtual plane HS parallel to the first
and second end surfaces 31a and 31b.
[0069] In addition to the advantageous effects produced by
Embodiment 1, the propeller-shaped impeller 60 for a railway
carriage air-conditioning apparatus according to the present
embodiment having the forward inclination angle .alpha. can
optimize at least the energy efficiency for producing an airflow,
the heat exchange efficiency of the first and second outdoor heat
exchangers 21a and 21b, or the noiselessness in the outdoor-unit
chamber R1.
Embodiment 3
[0070] FIGS. 2 and 3A do not clearly show a stagger angle
representing the inclination of the airflow producing units 32 and
62 for railway carriage air-conditioning apparatuses with respect
to a virtual plane parallel to the rotation shaft 41. The airflow
producing units 32 and 62 in which the sum of A+B is not greater
than 115 mm are sufficiently flat. Thus, the propeller-shaped
impellers 30 and 60 for railway carriage air-conditioning
apparatuses with a small stagger angle are less likely to contact
other components when turned over. Specific examples of a
propeller-shaped impeller for a railway carriage air-conditioning
apparatus with an airflow producing unit having a restricted
stagger angle will be described below.
[0071] As shown in FIG. 4A, a propeller-shaped impeller 70 for a
railway carriage air-conditioning apparatus according to the
present embodiment includes a boss 71 and an airflow producing unit
72 protruding from the boss 71 as in Embodiments 1 and 2, but
differs in that the airflow producing unit 72 has a stagger angle
.beta. restricted to 75.degree. or smaller. More specifically, the
stagger angle .beta. is restricted to 60.degree., or may be
smaller.
[0072] The stagger angle .beta. will be described with reference to
FIG. 4B. FIG. 4B is an expansion plan of a cross section of a blade
721 included in the airflow producing unit 72, taken along a side
surface of a virtual cylinder around the rotation shaft 41 of the
motor 40. In this expansion plan, the stagger angle .beta. refers
to an angle formed by a blade chord BC representing the chord and a
virtual plane VS parallel to the rotation shaft 41 of the motor 40.
When the stagger angle varies in the radial direction of the
rotation shaft 41, the stagger angle .beta. refers to the largest
stagger angle.
[0073] The propeller-shaped impeller 70 for a railway carriage
air-conditioning apparatus according to the present embodiment has
the stagger angle .beta. restricted to 75.degree. or smaller. In
addition to the advantageous effects of Embodiment 1, the
propeller-shaped impeller 70 for a railway carriage
air-conditioning apparatus thus prevents the rotation rate from
increasing excessively, and optimizes at least the energy
efficiency for producing an airflow, the heat exchange efficiency
of the first and second outdoor heat exchangers 21a and 21b, or the
noiselessness in the outdoor-unit chamber R1.
Embodiment 4
[0074] Although the sum of A+B is restricted to 115 mm or smaller
in the airflow producing units 62 and 72 in Embodiments 2 and 3,
the sum of A+B may exceed 115 mm. In this case, the airflow
producing units 62 and 72 may have a cutout to avoid contact with
other components. Specific examples will be described below.
[0075] As shown in FIG. 5, a propeller-shaped impeller 80 for a
railway carriage air-conditioning apparatus according to the
present embodiment includes a boss 81 and an airflow producing unit
82 protruding from the boss 81 as in Embodiments 1 to 3, but
differs in that the airflow producing unit 82 has a cutout 82a to
avoid contact with a corner of an upper surface of the motor
40.
[0076] The cutout 82a is defined by a portion of the airflow
producing unit 82 having a low height from one end to the other end
in the direction in which the rotation shaft 41 extends. More
specifically, the cutout 82a is defined by an inner peripheral
portion of the airflow producing unit 82 having a locally low
height adjacent to the rotation shaft 41 in the radial direction of
the rotation shaft 41.
[0077] The airflow producing unit 82 according to the present
embodiment has the sum of A+B of greater than 115 mm. The cutout
82a prevents the airflow producing unit 82 having a total height
higher than the airflow producing units 62 and 72 according to
Embodiments 2 and 3 from contacting the motor 40.
[0078] The airflow producing unit 82 has a degree of symmetry
defined by AB within the range of 1.0 to 1.3 inclusive as in
Embodiments 1 to 3. Thus, the airflow producing unit 82 attached to
the motor 40 while being turned over with the cutout 82a facing the
cover 12 shown in FIG. 1A does not contact the motor 40.
[0079] The present disclosure is not limited to the embodiments
described above, and may be modified in the following manners.
[0080] Although the rotation shaft 41 of the motor 40 extends
vertically and the outdoor blower 24 blows air upward and downward
in Embodiments 1 to 4, the rotation shaft 41 of the motor 40 may
extend in a direction other than the vertical direction. The
outdoor blower 24 may produce an airflow in a direction other than
the vertical direction, such as a lateral direction or an oblique
direction.
[0081] Although the airflow producing unit 32 shown in FIG. 7
includes three blades 321, the airflow producing unit 32 may
include any number of blades 321. The airflow producing unit 32 may
include two, four, or more blades 321.
[0082] In Embodiment 4, the cutout 82a of the airflow producing
unit 82 may have any shape. The cutout 82a may have any shape that
avoids interference with other components, and may be, for example,
circular, triangular, quadrangular, or in a shape combining
these.
[0083] The foregoing describes some example embodiments for
explanatory purposes. Although the foregoing discussion has
presented specific embodiments, persons skilled in the art will
recognize that changes may be made in form and detail without
departing from the broader spirit and scope of the invention.
Accordingly, the specification and drawings are to be regarded in
an illustrative rather than a restrictive sense. This detailed
description, therefore, is not to be taken in a limiting sense, and
the scope of the invention is defined only by the included claims,
along with the full range of equivalents to which such claims are
entitled.
[0084] This application claims the benefit of Japanese Patent
Application No. 2017-107436, filed on May 31, 2017, the entire
disclosure of which is incorporated by reference herein.
INDUSTRIAL APPLICABILITY
[0085] A railway carriage air-conditioning apparatus according to
the present disclosure is usable for air-conditioning a railway
carriage chamber. A propeller-shaped impeller according to the
present disclosure is particularly suitable for air-conditioning a
railway carriage chamber, but may have other uses.
REFERENCE SIGNS LIST
[0086] 10 Housing [0087] 11 Base frame [0088] 11a Bottom surface
[0089] 12 Cover [0090] 121 First vent [0091] 122a, 122b Second vent
[0092] 13 Partition plate [0093] 20 Air-conditioning apparatus
[0094] 21 Outdoor heat exchanger [0095] 21a First outdoor heat
exchanger [0096] 21b Second outdoor heat exchanger [0097] 22
Collaborative system [0098] 22a Expander [0099] 22b Indoor heat
exchanger [0100] 22c Vapor-liquid separator [0101] 22d Compressor
[0102] 22e Refrigerant pipe [0103] 23 Indoor blower [0104] 24
Outdoor blower [0105] 30, 60, 70, 80 Propeller-shaped impeller for
railway carriage air-conditioning apparatus [0106] 31, 61, 71, 81
Boss [0107] 32, 62, 72, 82 Airflow producing unit [0108] 321, 621,
721 Blade [0109] 31a First end surface [0110] 31b Second end
surface [0111] 40 Motor [0112] 41 Rotation shaft [0113] 42 Bearing
surface [0114] 50 Bellmouth [0115] 82a Cutout [0116] 90
Propeller-shaped impeller for railway carriage air-conditioning
apparatus [0117] 91 Upper end portion [0118] 100 Railway carriage
air-conditioning apparatus [0119] R1 Outdoor-unit chamber [0120] R2
Indoor-unit chamber [0121] CL Blade centerline [0122] HS, VS
Virtual plane [0123] BC Blade chord
* * * * *