Patent Application
20200269885
The present disclosure relates to a propeller-shaped impeller and a railway carriage air-conditioning apparatus.
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.
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.
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.
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.
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.
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.
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≥B.
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.
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.
The overall structure of a railway carriage air-conditioning apparatus 100 according to the present embodiment will be described with reference to
The housing 10 shown in
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.
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.
The air-conditioning apparatus 20 shown in
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.
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.
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.
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.
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.
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
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.
As shown in
As shown in
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.
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.
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.
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.
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.
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.
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
As shown in
As shown in
To produce an airflow shown in
Following the comparative example described above, the present embodiment will be described again with reference to
As shown in
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.
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.
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.
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.
As shown in
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.
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≥B) in
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
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.
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.
As shown in
In the present embodiment, the forward inclination angle α is not greater than 40°. 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°.
The forward inclination angle α will be described with reference to
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 α 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.
As shown in
The stagger angle β will be described with reference to
The propeller-shaped impeller 70 for a railway carriage air-conditioning apparatus according to the present embodiment has the stagger angle β restricted to 75° 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.
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.
As shown in
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.
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.
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
The present disclosure is not limited to the embodiments described above, and may be modified in the following manners.
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.
Although the airflow producing unit 32 shown in
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.
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.
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-107436 | May 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/019502 | 5/21/2018 | WO | 00 |
