Patent Grant
9605686
The present invention relates to an axial flow fan that includes a plurality of blades and an air-conditioning apparatus that includes the axial flow fan.
View (a) of
View (b) of
View (c) of
View (d) of
As illustrated in
In the axial flow fan, when the blades 1 of the axial flow fan rotate, the fluid present between the blades 1 collides with the blade surfaces. The pressure is increased in the surfaces with which the fluid collides, and the fluid is pushed in the axis of rotation direction and moved.
When the blades 1 rotate, the fluid is affected by the centrifugal force and the shape of the blades 1. Thus, as illustrated in
Since the axial flow fan is disposed in a bell-mouth 13, the fluid flows in the axis of rotation direction instead of spread in the radial directions.
A pressure loss occurs when the flow velocity distribution, in the axial direction, of the blade 1 of the axial flow fan, as illustrated in
First, a pressure loss ξ of the fluid is given by:
where C is the pressure loss coefficient, which is approximately 1 for an open space, ρ is the air density, and v is the flow velocity.
Since the velocity distribution of the fluid varies from one position to another position in the radial direction of the blade, the pressure loss ξ is calculated by dividing the fluid into minute regions.
The square of the flow velocity Vrms of the fluid in one of the minute regions is the sum of the square of an average flow velocity Vave and the square of the standard deviation σ, and accordingly, is given by:
Vrms2=Vave2+σ2 [Math. 2]
where Vave is the average flow velocity [m/s] of the fluid, and
σ is the standard deviation [m/s], which is an index representing a deviation from the average flow velocity.
Thus, the pressure loss ξ of the fluid is the sum of squares of the flow velocities in the minute regions and given by Math. 3.
The number of minute regions is the number of equally divided regions (in this case, ten equally divided regions) of the blade 1 in the radial direction.
where
ρ is the air density [kg/m3],
v1 to v10 are the local average velocities [m/s] in the case of ten regions equally divided in the radial direction,
Vave is the average flow velocity [m/s], and
σ is the standard deviation [m/s], which is an index representing a deviation from the average flow velocity.
From Maths. 2 and 3. Math. 4 is obtained to calculate the standard deviation σ [m/s], which is an index representing a deviation from the average flow velocity:
Math. 3, therefore, reveals that, in order to reduce the pressure loss ξ, σ need only be zero. That is, from the viewpoint of reducing the pressure loss, it is advantageous that the velocity distribution, in the axis of rotation direction, over positions in the radial direction of the blade is ideally flat (uniform flow, that is, the flow velocity is uniform in any position in the radial direction). The flat velocity distribution is achieved by equalizing the velocity distribution by decreasing the high velocity area and increasing the low velocity area.
[Patent Literature 1] Japanese Unexamined Patent Application Public ion No. 2012-12942 (see FIG. 4, etc.)
When the velocity distribution, in the axis of rotation direction, is uniform over the positions in the radial direction of the blade as described above, the pressure loss of the axial flow fan can be reduced. However, in the example of the related-art axial flow fan as illustrated in
The present invention has been made in order to address the above-described problem, and has as its object to obtain an axial flow fan, with which the power consumption of a drive motor can be reduced, and an air-conditioning apparatus that includes the axial flow fan. In the axial flow fan, the pressure loss of air blown from the fan is reduced by improving the shape of blades of the axial flow fan by increasing or decreasing the blade areas on the inner circumferential side and the outer circumferential side of the blades, so as to flatten the velocity distribution, in the axis of rotation direction, over positions in the radial direction of the blade.
An axial flow fan according to the present invention includes a plurality of blades rotated to deliver a fluid from the upstream side to the downstream side of a flow of the fluid in a direction along an axis of rotation. Each of the plurality of blades includes a first curved portion, a second curved portion, and a third curved portion. The first curved portion is formed on a leading edge on a forward side of the blade in a rotational direction in which the blade rotates. The first curved portion protrudes backwards in the rotational direction in a planar image of the blade as projected in the direction along the axis of rotation. The first curved portion has a leading-edge rearmost point as a point of contact where the first curved portion is in contact with a virtual line that extends perpendicularly to the axis of rotation. The second curved portion is formed on a trailing edge on a backward side of the blade in the rotational direction. The second curved portion is located on the inner circumferential side of the trailing edge and protrudes backwards in the rotational direction in a planar image of the blade as projected in the direction along the axis of rotation. The third curved portion is formed on the trailing edge on the backward side of the blade in the rotational direction. The third curved portion is located on the outer circumferential side of the blade on the trailing edge and protrudes forwards in the rotational direction in a planar image of the blade as projected in the direction along the axis of rotation. The third curved portion has a trailing-edge foremost point as a point of contact where the third curved portion is in contact with another virtual line that extends perpendicularly to the axis of rotation. The second curved portion has a trailing-edge rearmost point at which the length of a perpendicular line dropped to the other virtual line that passes through the axis of rotation and the trailing-edge foremost point takes a maximum. A first intersection that is an intersection between the trailing edge and a first concentric circle, which is one of concentric circles having as their center the axis of rotation and passes through the leading-edge rearmost point, is located between the trailing-edge rearmost point and the trailing-edge foremost point.
With the axial flow fan according to the present invention, the velocity distribution, in the axis of rotation direction, over the positions in the radial direction of the blade is flat, Thus, the pressure loss of the fluid blown from the axial flow fan is decreased, and accordingly, the drive force for rotating the axial flow fan can be reduced.
It should be noted that a “propeller fan” will be taken as an exemplary example of the “axial flow fan” hereinafter.
The structure of a propeller fan according to Embodiment 1 will be described with reference to
View (a) of
View (b) of
View (a) of
View (b) of
View (c) of
In the propeller fan according to Embodiment 1, a plurality of blades 1 are fixed to the circumferential wall of a cylindrical boss 2, to be engaged with a drive shaft rotated by a motor or the like, while the boss 2 is positioned at its center. Each blade 1 is slanted at a predetermined angle relative to an axis of rotation 2a of the boss 2. As the propeller fan rotates, a fluid present between the blades 1 is pushed by blade surfaces and delivered in a fluid flow direction 5 in which the fluid flows. Note that one surface of each blade 1 that pushes the fluid and rises in pressure will be referred to as a pressure surface 1a hereinafter, while the other surface that is formed on the back side of the pressure surface 1a and drops in pressure will be referred to as a suction surface 1b hereinafter.
The blades 1 rotate in a rotational direction 3 using a rotational force transmitted to the boss 2. Then, the fluid present between the blades 1 flows in on the side of the pressure surface 1a in an inflow direction 4.
The shape of each blade 1 is defined by a leading edge 10 on the forward side of the blades 1 in the rotational direction 3 in which the blades 1 rotate, a trailing edge 20 on the backward side in the rotational direction 3 in which the blades 1 rotate, and an outer circumferential edge 12 defining the outer circumference of the blades 1.
The shape of each blade 1 projected in the axis of rotation direction of the boss 2 will be described next.
As illustrated in view (a) of
The first curved portion 10a of the leading edge 10 has a leading-edge rearmost point 11 as a point of contact where the first curved portion 10a is in contact with a virtual line 8, which extends perpendicularly to the axis of rotation 2a of the boss 2.
That is, the leading-edge rearmost point 11 is defined as, out of intersections between the first curved portion 10a and the virtual line 8 extending perpendicularly to the axis of rotation 2a of the boss 2, a rearmost point in the rotational direction 3.
A substantially triangular region P is formed in the blade 1 when the virtual line 8 passes through the leading-edge rearmost point 11. The region P is surrounded by a virtual line 8A, the leading edge 10, and the circumferential surface of the boss 2. The region P is represented by hatching in view (a) of
Also in the blade 1, a second curved portion 20a and a third curved portion 20b are formed on the trailing edge 20 on the backward side in the rotational direction 3. In a planar image of the blade 1 as projected in the direction along the axis of rotation 2a of the boss 2, the second curved portion 20a is located on the inner circumferential side of the trailing edge 20 and protrudes backwards in the rotational direction 3, and the third curved portion 20b is located on the outer circumferential side of the blade 1 on the trailing edge 20 and protrudes forwards in the rotational direction 3.
The third curved portion 20b has a trailing-edge foremost point 23 as a point of contact where the third curved portion 20b is in contact with a virtual line 8B, which extends perpendicularly to the axis of rotation 2a of the boss 2.
The second curved portion 20a has a trailing-edge rearmost point 24. The distance between the second curved portion 20a and the virtual line 8B, which passes through the axis of rotation 2a of the boss 2 and the trailing-edge foremost point 23, along a line perpendicular to the virtual line 8B is longest at the trailing-edge rearmost point 24.
A first intersection 25 is an intersection between the ailing edge 20 and a first concentric circle 9a, which is one of concentric circles about the axis of rotation 2a of the boss 2 and passes through the leading-edge rearmost point 11. The first intersection 25 is located between the trailing-edge rearmost point 24 and the trailing-edge foremost point 23.
That is, a region Q is formed on the inner circumferential side of the trailing edge 20 of the blade 1. The region Q is surrounded by the second curved portion 20a and a virtual line 8C that passes through the first intersection 25. The region Q is defined with respect to the virtual line 8C and serves as an increment by which the area of the blade 1 increases. The region Q is represented by hatching in view (a) of
Furthermore, a region R is formed on the outer circumferential side of the blade 1 on the trailing edge 20 of the blade 1. The region R is surrounded by the third curved portion 20b and the virtual line 8C that passes through the first intersection 25. The region R is defined with respect to the virtual line 8C and serves as a decrement by which the area of the blade 1 decreases.
The shape of each blade 1 projected in a direction perpendicular to the axis of rotation 2a of the boss 2 will be described next.
View (c) of
As illustrated in
In Embodiment 1, the blade 1 has a shape in which the chord center line 6 is located upstream of the perpendicular plane 7 in the flow of the fluid (to be referred to as a “forward swept shape” hereinafter).
The distribution of the velocity distribution, in the axial direction, of each blade 1 of the propeller fan having such a structure will be described with reference to
Referring to
The velocity distribution 30 (forward swept shape) represented by a broken line is obtained when the blade 1 does not have the set of regions P, Q, and R, and the velocity distribution 31 (corrected, forward swept shape) represented by the solid line is obtained when the blade 1 has the set of regions P, Q, and R.
In Embodiment 1, since the regions P, Q, and R are set on the blade surface, the effects of increasing or reducing the flow velocity are produced in the velocity distribution to obtain a region Vp in which the flow velocity is increased by the effect of the region P, a region Vq in which the flow velocity is increased by the effect of the region Q, and a region Vr in which the flow velocity is reduced by the effect of the region R.
The above description reveals that, when the blade 1 does not have the set of regions P, Q, and R, the flow velocity is higher on the outer circumferential side of the blade 1, and, when the blade 1 has the set of regions P, Q, and R, a high flow velocity region is formed on the inner circumferential side of the blade 1 and the velocity is reduced in a high flow velocity region on the outer circumferential side of the blade 1.
Since the flow velocity distribution is flat as described above, the pressure loss of air blown from the propeller fan is reduced, and accordingly, a drive force for rotating the propeller fan can be reduced. Thus, the power consumption of the motor can be reduced,
In Embodiment 1, in the example of the shape of the blade 1 of the propeller fan, the first intersection 25 that is an intersection between the trailing edge 20 and the first concentric circle 9a, which has as its center the axis of rotation 2a of the boss 2 and passes through the leading-edge rearmost point 11, is located between the trailing-edge rearmost point 24 and the trailing-edge foremost point 23. In Embodiment 2, the structure according to Embodiment 1 is more specifically defined in terms of the relationship between the first intersection 25 and the shape of the trailing edge 20
Referring to
In this case, however, an inflection point 26 is additionally defined. A second curved portion 20a and a third curved portion 20b of a trailing edge 20 are connected to each other at the inflection point 26.
In Embodiment 2, the blade 1 has a shape in which the first intersection 25 and the inflection point 26 are located at the same position on the trailing edge 20. That is, the inflection point 26 is located on a first concentric circle 9a, which has as its center an axis of rotation 2a and passes through the leading-edge rearmost point 11.
Note that, as described above, a region P increases the flow quantity on the inner circumferential side of the blade 1 and a region R decreases the flow quantity on the outer circumferential side of the blade 1. Thus, the velocity distribution is equalized. That is, since the effect produced by the region P and the effect produced by the region R are opposite to each other in terms of changes in flow quantity, when the inflection point 26 is more to the inner circumferential side than the first intersection 25, the flow rate increased by the region P is decreased by the region R.
This unnecessarily reduces, using the trailing edge 20, the flow rate increased using the leading edge 10, and accordingly, is inefficient from the viewpoint of equalizing the velocity distribution of the blade 1.
Since the leading-edge rearmost point 11 and the inflection point 26 are located on the first concentric circle 9a in Embodiment 2, the flow rate increased by the leading edge 10 is not decreased by the trailing edge 20 and remains effective. Since regions where the flow rate is low can be efficiently increased and regions where the flow rate is high can be efficiently reduced, the velocity distribution can be equalized. With this arrangement, the drive force for rotating the propeller fan can be reduced to, in turn, reduce the power consumption of the motor.
In Embodiment 3, the relationship between the first intersection 25 and the shape of the trailing edge 20 in Embodiments 1 and 2 are more specifically defined.
Referring to
In general, the air sending performance of the propeller fan is represented by the relationship between the pressure (static pressure) of a fluid and the flow quantity per unit time (P-Q chart) as illustrated in
An intersection between the normal pressure loss curve A and the capacity-characteristic curve C is a normal operating point, and an intersection between the high pressure loss curve B and the capacity-characteristic curve C is a high pressure loss operating point.
View (a) of
Dotted lines in view (b) of
Obviously, in the case of the high pressure loss operating point, the streamline limits 14 shift to the outer circumferential side of the blade 1 relative to those in the case of the normal operating point.
That is, in operating the propeller fan, when a high static-pressure fan is required due to a high pressure loss caused by the resistance in the flow passage, the path of the streamline limit 14 on each blade 1 of the propeller fan is as follows: that is, as illustrated in view (b) of
Thus, the blade 1 according to Embodiment 3 has, as illustrated in
It has been clarified by the result of the numerical fluid dynamics analysis that the path of the streamline limit 14 of the fluid having flowed through the leading-edge rearmost point 11 shifts to the outer circumferential side in a region on the inner circumferential side of the second concentric circle 9b, with a radius larger than that of the first concentric circle 9a by 0.1r.
As described above, in Embodiment 3, the inflection point 26 is positioned more to the outer circumferential side of the blade 1 than the first intersection 25. Thus, even when the streamline limits 14 shift to the outer circumferential side, the flow quantity increased by the region P is not decreased by the region R.
That is, since the blade 1 has a shape in which the inflection point 26 is located between the first intersection 25 and the second intersection 27, when the propeller fan is used as a high static-pressure propeller fan with which the streamline limits 14 shift to the outer circumferential side of the blade 1, the flow velocity distribution of the fluid can be flattened. Thus, the pressure loss of the fluid blown from the propeller fan is reduced to, in turn, reduce the drive force for rotating the propeller fan. This reduces the power consumption of the motor.
In Embodiment 1, the blades 1 of the propeller fan have the forward swept shape. In Embodiment 4, the blades 1 of the propeller fan have a backward swept shape.
View (a) of
In view (a) of
Thus, in Embodiment 4, the blade 1 has a shape in which the chord center line 6 is located downstream of the perpendicular plane 7 in the flow of the fluid (to be referred to as a “backward swept shape” hereinafter).
For comparison, in the forward swept propeller fan illustrated in view (b) of
An arrow illustrated in view (a) of
For comparison with the contrast, in the forward swept propeller fan is illustrated in view (b) of
The difference in velocity distribution in a direction perpendicular to the axis of rotation between the forward and backward swept propeller fans will be described next with reference to
The velocity distribution of the forward swept propeller fan is, as illustrated in
View (a) of
At a position where the velocity distribution has a highest velocity (the flow quantity is large), the blown air is pushed by the blade 1 in different directions, as mentioned earlier. Thus, the peak position of the backward swept shape tends to shift more to the inner circumferential side of the blade 1 than the forward swept shape.
Views (b) and (c) of
View (d) of
As illustrated in view (d) of
Accordingly, the pressure loss of air blown from the propeller fan is reduced, and accordingly, the drive force required for sending air is reduced. Thus, the power consumption of the motor can be reduced.
Although the chord center line 6 of the backward swept shape is entirely located downstream of the perpendicular plane 7 in the flow of the fluid in the blade shape of the above-described example, the blade 1 still has the functions and produces the effects as described above as long as the blade 1 has a shape in which 70% of the chord center line 6 in length is located downstream of the perpendicular plane 7 in the flow of the fluid.
The structure, in which the propeller fan having the backward swept blades 1 according to Embodiment 4 is attached to motor supports 70, will further be described hereinafter.
View (a) of
The above-described backward swept blades 1 each have a shape in which the chord center line 6 is located downstream of the perpendicular plane 7 in the flow of the fluid. In the backward swept propeller fan illustrated in view (a) of
View (b) of
View (c) of
View (d) of
When the propeller fans illustrated in views (a) and (b) of
At this time, the Karman vortex street 71, as cut apart, collides with a portion of the blades 1 near the leading edges 10, thereby causing a large pressure fluctuation. As a result, so-called aerodynamic noise is generated. The aerodynamic noise is known to increase noise. The Karman vortex street 71 is attenuated as it moves to the downstream side.
In the forward swept propeller fan illustrated in view (b) of
In contrast, in the backward swept propeller fan illustrated in view (a) of
An outdoor unit of an air-conditioning apparatus attaining low noise can be provided using such a built-in propeller fan, as illustrated in view (d) of
<Structure to Which Propeller Fans According to Embodiments 1 to 4 Are Applicable>
The detailed structure of the blades 1 that can be added to the propeller fans according to each of Embodiments 1 to 4 will be described next.
[Winglet]
The shape of the outer circumferential edge 12 of the blade 1 according to each of Embodiments 1 to 4 will be described.
View (a) of
View (b) of
In views (a) and (b) of
In the propeller fan, when the blade 1 rotates, a flow of the fluid from the high static-pressure side, that is, the side of a pressure surface 1a to the low static-pressure side, that is, the side of a suction surface 1b is generated on the outer circumferential edge 12 of the blade 1. A wingtip vortex is formed by this flow. The wingtip vortex has a spiral vortex structure.
The wingtip vortex generated in the preceding blade 1 flows into the succeeding blade 1, interferes with the succeeding blade 1, and collides with the wall surface of a bell-mouth disposed around the propeller fan, so that a static pressure fluctuation occurs. This increases noise and motor input. The winglet 40 produces the effect of suppressing the wingtip vortex as illustrated in view (b) of
It is desirable that letting r be the radius of the blade 1 having as its center the axis of rotation 2a, the winglet 40 should be disposed more to the outer circumferential side than a position that is separated from the axis of rotation 2a by 0.8r. This is done to allow the winglet 40 to produce effects of both suppressing the wingtip vortex and improving the bending strength of the blade 1.
With such a winglet 40, the occurrence of a wingtip vortex and the pressure fluctuation occurring when the blade 1 passes at high speed near the bell-mouth are suppressed to reduce noise.
[Cross-sectional Shape of Trailing Edge]
The cross-sectional shape of the trailing edge 20 of the blade 1 according to each of Embodiments 1 to 4 will be described.
View (a) of
View (b) of
View (c) of
View (d) of
The cross-section of the blade 1 illustrated in views (c) and (d) of
As illustrated in view (c) of
Note that in the blade cross-section, a cross-sectional radius r1 of the first arc 20c continuous with the pressure surface 1a is specified to be larger than a cross-sectional radius r2 of the second arc 20d continuous with the suction surface 1b.
In order to clearly describe the difference in the flow of the fluid corresponding to the cross-sectional radii of the first arc 20c and the second arc 20d of the trailing edge 20, in the cross-section of the blade 1 illustrated in view (a) of
Streamlines near the blade surface are illustrated in views (a) and (b) of
In doing so, in the cross-sectional shape of the trailing edge 20 illustrated in view (a) of
As illustrated in view (b) of
Although the cross-sectional shape of the entire trailing edge 20 has the first arc 20c and the second arc 20d in the above-described example, it may be applied only to the third curved portion 20b on the outer circumferential side, which is a region where the flow velocity is high in the trailing edge 20.
[Shape of Connection of Trailing Edge and Boss]
The shape of a connecting portion 60, where the boss 2 and the inner circumferential side of the trailing edge 20 are connected to each other, according to each of Embodiments 1 to 4 will be described.
Views (a) and (b) of
Referring to
The reason for this will be given with reference to
Referring to
As illustrated in
As is generally known, it is often the case that, when the propeller fan is formed of resin or the like, cracks develop from portions to which tensile forces are applied, resulting in breakage of propeller fans. In order to avoid such a situation, it is desirable that the center of gravity 61 should be positioned near the boss 2.
The centrifugal force is given by a fundamental equation as:
where F is the centrifugal force, m is the mass, a is the acceleration, v is the velocity, and ω is the angular acceleration.
When the effects on the centrifugal force 65a produced on the inner circumferential side of the blade 1 are compared with those on the outer circumferential side of the blade 1, it can be understood that, although the mass on the outer circumferential side and that on the inner circumferential side are the same, the mass on the outer circumferential side has an influence at a higher rate on the centrifugal force 65a than that on the inner circumferential side because the radius r is a multiplier. That is, the smaller the mass at a position farther than the axis of rotation 2a, the smaller the centrifugal force 65a, and accordingly, the smaller the resultant force 65c can become.
In the propeller fan according to each of Embodiments 1 to 4, with the third curved portion 20b, which reduces the area of the blade 1, on the outer circumferential side of the blade 1 on the trailing edge 20 of the blade 1, the effects on the centrifugal force 65a can be reduced. Thus, the tensile force applied to the connecting portion 60, where the trailing edge 20 and the boss 2 are connected to each other, is reduced. Accordingly, the tensile force can be addressed even when the connecting portion 60 has the edge shape that is not rounded and has the valley fold line.
Accordingly, the amount of resin for a rounding process can be reduced to obtain a lightweight fan, and the power consumption of the motor, in turn, can be reduced.
[Packing of Propeller Fans]
Packing of propeller fans according to each of Embodiments 1 to 4 will be described.
Referring to
Since the propeller fans are packed as described above, when the cardboard box 81 having been transported by truck and delivered to the factory is opened, contamination adhering to the cardboard, dust, dirt, and the like floating in the factory can be prevented from entering the bosses 2.
Thus, unstable rotation or noise due to deviation of the shaft center of the propeller fan, which is caused by the dirt caught between the axial hole of the boss 2 and the motor shaft, can be avoided.
[Propeller Fan without Boss]
Although the example of the propeller fan includes a boss, and the blades 1 are attached to the circumferential surface of the boss 2 in Embodiments, the structure of the blade 1 according to Embodiments can be applied to a propeller fan without a boss as illustrated in
Even when a propeller fan without a boss is used, the velocity distribution of the flow in the rotational direction over the positions in the radial direction of the blade 1 is flattened by forming the regions P, Q, and R in the blade 1 as illustrated in
[Application to Outdoor Unit]
Views (a) and (b) of
The propeller fan according to each of Embodiments 1 to 4 used for an outdoor unit 90 is disposed in the outdoor unit 90 together with a bell-mouth 13 and sends outdoor air to an outdoor heat exchanger for exchanging heat. In doing so, since the velocity distribution of blown air in the axis of rotation direction is equalized over the positions in the radial direction of the blade of the propeller fan, the outdoor unit 90 featuring a reduced pressure loss and reduced power consumption can be realized.
The blade shape of the propeller fan described in Embodiments can be used in various air-sending devices. Other than the outdoor unit, for example, the blade shape of the propeller fan can be used in an indoor unit of the air-conditioning apparatus. Furthermore, the blade shape of the propeller fan according to Embodiments can be widely applied to the blade shapes of, for example, general air-sending devices, ventilating fans, pumps, and axial flow compressors that deliver a fluid.
1 blade, 1a pressure surface, 1b suction surface, 2 boss, 2a axis of rotation, 2b lid surface, 3 rotational direction, 4 inflow direction, 5 fluid flow direction, 6 chord center line, 6a contact point, 7 perpendicular plane, 8A, 8B, SC virtual line, 9 concentric circle, 9a first concentric circle, 9b second concentric circle, 10 leading edge, 10a first curved portion, 11 leading-edge rearmost point, 12 outer circumferential edge, 13 bell-mouth, 14 streamline limit, 15 fluid pushing direction, 20 trailing edge, 20a second curved portion, 20b third curved portion, 20c first arc, 20d second arc, 23 trailing-edge foremost point, 24 trailing-edge rearmost point, 25 first intersection, 26 inflection point, 27 second intersection, 40 winglet, 50 cross-sectional position, 51 separation region, 60 connecting portion, 61 center of gravity, 65a centrifugal force, 65b tensile force, 65c resultant force, 70 motor support, 71 Karman vortex street, 81 cardboard box, and 90 outdoor unit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-165454 | Aug 2013 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 77888 | Kennedy | May 1868 | A |
| 1895252 | Kontos | Jan 1933 | A |
| 20150044058 | Hamada et al. | Feb 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 204239327 | Apr 2015 | CN |
| 2 607 714 | Jun 2013 | EP |
| 2000-018194 | Jan 2000 | JP |
| 2005140081 | Jun 2005 | JP |
| 2006-063879 | Mar 2006 | JP |
| 2006177205 | Jul 2006 | JP |
| 2010-101223 | May 2010 | JP |
| 2010-150945 | Jul 2010 | JP |
| 2012-012942 | Jan 2012 | JP |
| Entry |
|---|
| Office Action issued Nov. 10, 2015 in the corresponding JP application No. 2013-165454 (with English translation). |
| Office Action dated Apr. 1, 2016 issued in corresponding CN patent application No. 201410389328.7 (and English translation). |
| Communication pursuant to Article 94(3) EPC issued on Jul. 13, 2016 in corresponding EP patent application No. 14 179 447.9. |
| Office Action issued Aug. 1, 2016 in the corresponding CN application No. 201410389328.7 (with English translation). |
| Extended European Search Report dated Jul. 2, 2015 issued in corresponding EP patent application No. 14179447.9. |
| Shingo Hamada et al., “Aerodynamic Noise Simulation of Propeller Fan by Large Eddy Simulation”. Academic Journal of Japan Society of Refrigerating and Air Conditioning Engineers, Jul. 2009, vol. 84, No. 981, p. 34, Fig. 13(d). |
| Number | Date | Country | |
|---|---|---|---|
| 20150044058 A1 | Feb 2015 | US |
