This application is a U.S. national stage application of International Application No. PCT/JP2015/080937, filed on Nov. 2, 2015, the contents of which are incorporated herein by reference.
The present invention relates to an outdoor unit for use in an air conditioner and a refrigeration cycle device.
An outdoor unit of an air conditioner is sometimes installed in a narrow space due to architectural circumstances and the like. In this case, an adequate space is not available between an outlet side of the outdoor unit and a wall surface of a building. Thus, there is no adequate air outlet passage on the outlet side of the outdoor unit, causing an increase in draft resistance. Accordingly, a radial velocity component of an outlet flow from the outdoor unit increases, while its axial velocity component decreases.
The configuration of an outdoor unit installed in a narrow space as described above is disclosed, for example, in Japanese Patent Laying-Open No. 4-251138 (see PTD 1). In PTD 1, a ring is mounted on an outlet port of an orifice. This ring has an inner diameter dimension slightly greater than an outer diameter dimension of an impeller, and has the shape of a drop of water in cross section.
According to PTD 1, an air flow blown obliquely from the impeller is caused by the ring to be blown along an inner circumferential surface of the ring and a wall surface of the outlet port of the orifice, thereby not causing degradation in performance of a blower and an increase in noise.
PTD 1: Japanese Patent Laying-Open No. 4-251138
However, PTD 1 does not consider the fact that a radial velocity component of the outlet flow varies in a circumferential direction depending on the conditions on the intake side. Depending on the conditions on the intake side, the air flow blown from the impeller does not flow sufficiently along the wall surface of the outlet port of the orifice, causing an increase in draft resistance and an increase in noise.
The present invention was made in view of the aforementioned problems, and has an object to provide an outdoor unit of an air conditioner having low draft resistance and low noise.
One outdoor unit of an air conditioner of the present invention includes a casing, an impeller, and a bell mouth. The casing has an air outlet port. The impeller is disposed in the casing and rotatable about a rotating shaft. The bell mouth surrounds an outer periphery of the impeller. The bell mouth has a straight pipe portion and a curved portion. The straight pipe portion surrounds the outer periphery of the impeller. The curved portion is located between the straight pipe portion and the air outlet port, and increases in diameter from the straight pipe portion toward the air outlet port. The casing has a wall portion surrounding the impeller, as seen in an axial direction of the rotating shaft. The wall portion has a first portion, and a second portion located further away from a center of rotation of the rotating shaft than the first portion, as seen in the axial direction. The curved portion has a first curved surface portion located on a line connecting the center of rotation and the first portion, and a second curved surface portion located on a line connecting the center of rotation and the second portion, as seen in the axial direction. A radius of curvature of the second curved surface portion is greater than a radius of curvature of the first curved surface portion.
Another outdoor unit of an air conditioner of the present invention includes a casing, an impeller, and a bell mouth. The casing has an air outlet port. The impeller is disposed in the casing and rotatable about a rotating shaft. The bell mouth surrounds an outer periphery of the impeller. The bell mouth has a straight pipe portion and a flared portion. The straight pipe portion surrounds the outer periphery of the impeller. The flared portion is located between the straight pipe portion and the air outlet port, and increases in diameter from the impeller toward the air outlet port. The casing has a wall portion surrounding the impeller, as seen in an axial direction of the rotating shaft. The wall portion has a first portion, and a second portion located further away from a center of rotation of the rotating shaft than the first portion, as seen in the axial direction. The flared portion has a first extending portion located on a line connecting the center of rotation and the first portion, and a second extending portion located on a line connecting the center of rotation and the second portion, as seen in the axial direction. The first extending portion has a first dimension along the axial direction. The second extending portion has a second dimension along the axial direction. The second dimension is greater than the first dimension.
According to the one outdoor unit of an air conditioner of the present invention, the radius of curvature of the curved portion of the bell mouth is set to be greater in the portion in which the length from the center of rotation of the impeller to the wall surface of the casing is greater than in the portion in which the aforementioned length is smaller. Thus, an air flow can be flown along the curved portion in the portion of the greater length. Accordingly, draft resistance and noise can be reduced.
According to the another outdoor unit of an air conditioner of the present invention, the axial dimension of the flared portion is set to be greater in the portion in which the length from the center of rotation of the impeller to the wall surface of the casing is greater than in the portion in which the aforementioned length is smaller. Thus, an air flow can be flown along the curved portion in the portion of the greater length. Accordingly, draft resistance and noise can be reduced.
Embodiments of the present invention will now be described with reference to the drawings.
It should be noted that the same or corresponding elements are designated by the same reference characters in
First Embodiment
As shown in
Casing 1 has a front panel 1a, a pair of right and left side panels 1b, a back panel 1c, a top panel 1d, a bottom panel 1e, and a separator 1f. These panels 1a to 1e are assembled into a substantially rectangular parallelepiped shape, whereby casing 1 has a box shape. Separator if is disposed in an internal space of casing 1. This separator 1f separates the internal space of casing 1 into a machine room 11 and a blower room 12.
A compressor (not shown) and the like are disposed in machine room 11. Impeller 3, bell mouth 4, driving source 5, rotating shaft 6, outdoor heat exchanger 7 and the like are disposed in blower room 12.
Outdoor heat exchanger 7 has an L-shape, for example, in a plan view of
Casing 1 is provided with air intake ports 1ba and 1ca on at least two surfaces thereof. Air intake port 1ba is provided on side panel 1b, and air intake port 1ca is provided on back panel 1c. Air can be sucked from the outside of casing 1 to the inside of casing 1 through each of air intake ports 1ba and 1ca. The air that has been sucked into casing 1 through air intake ports 1ba and 1ca can exchange heat with outdoor heat exchanger 7.
Casing 1 is provided with an air outlet port 1aa. This air outlet port 1aa is provided on front panel 1a. Air can be blown from the inside of casing 1 to the outside of casing 1 through air outlet port 1aa. Accordingly, the air that has exchanged heat with outdoor heat exchanger 7 is blown to the outside of casing 1 through air outlet port 1aa.
Driving source 5 is a fan motor, for example. Driving source 5 is disposed in front of outdoor heat exchanger 7. Driving source 5 is attached to casing 1 with a driving source support plate (not shown) interposed therebetween.
Impeller 3 is attached to driving source 5 with rotating shaft 6 interposed therebetween. Impeller 3 is disposed in front of driving source 5. Impeller 3 is for generating air circulation for efficient heat exchange in outdoor heat exchanger 7. Impeller 3 can rotate around an axis CL of rotating shaft 6, with a driving force supplied from the driving source. Impeller 3 has the function of rotating to introduce outdoor air into blower room 12 through each of air intake ports 1ba and 1ca, and then to discharge the air to the outside of casing 1 through air outlet port 1aa.
Bell mouth 4 is attached to a backside surface (rear surface) of front panel 1a. Bell mouth 4 is disposed to surround an outer periphery of impeller 3. Bell mouth 4 has a straight pipe portion 4a, a reduced diameter portion 4b, a curved portion 4c, and a flared portion 4d. Straight pipe portion 4a, reduced diameter portion 4b, curved portion 4c and flared portion 4d are integrally formed to constitute a single component.
Straight pipe portion 4a surrounds the outer periphery of impeller 3. Straight pipe portion 4a has a cylindrical shape, and extends from the front toward the back while maintaining a diameter of the cylinder. Reduced diameter portion 4b is connected to a back end of straight pipe portion 4a. Reduced diameter portion 4b has a tubular shape, and is formed such that an opening diameter of the tubular shape decreases from a back end toward a front end. Reduced diameter portion 4b has the smallest opening diameter at a joint with straight pipe portion 4a.
Curved portion 4c is connected to a front end of straight pipe portion 4a. Curved portion 4c is located between straight pipe portion 4a and air outlet port 1aa. Curved portion 4c increases in diameter from straight pipe portion 4a toward air outlet port 1aa. Accordingly, an opening diameter OD of curved portion 4c (
Flared portion 4d is connected to a front end of curved portion 4c. Flared portion 4d is located between curved portion 4c and air outlet port 1aa. Flared portion 4d increases in diameter from curved portion 4c toward air outlet port 1aa. Accordingly, in flared portion 4d, the opening diameter of bell mouth 4 increases from curved portion 4c toward air outlet port 1aa. At least an inner peripheral surface of flared portion 4d is formed linearly in the cross section shown in
As shown in
As seen in the axial direction of rotating shaft 6, wall portions 1b, 1d, 1e and 1f surrounding impeller 3 have portions of different lengths from a center of rotation C of impeller 3 (a point on axis CL in
Specifically, the aforementioned portion S1 is a portion on side panel 1b, the aforementioned portion S2 is a portion (corner) where side panel 1b and top panel 1d intersect each other, and the aforementioned portion S3 is a portion on top panel 1d.
As seen in the axial direction of rotating shaft 6, length L2 between the aforementioned S2 and center of rotation C is greater than length L1 between the aforementioned S1 and center of rotation C, and length L3 between the aforementioned S3 and center of rotation C. That is, the aforementioned portion S2 is located further away from center of rotation C than the aforementioned portions S1 and S3.
Curved portion 4c has, for example, a curved surface portion (first curved surface portion) P1, a curved surface portion (second curved surface portion) P2, and a curved surface portion (third curved surface portion) P3. As seen in the axial direction of rotating shaft 6 as shown in
A cross section of outdoor unit 10 along the aforementioned straight line SL1 is shown in
A radius of curvature R2 of curved surface portion P2 shown in
As described above, in bell mouth 4 of the present embodiment, as seen in the axial direction of rotating shaft 6 as shown in
It should be noted that the radius of curvature of curved portion 4c may continuously vary in a circumferential direction around center of rotation C, as shown in
A front end 4e of bell mouth 4 may protrude forward past front panel 1a, as long as it is located behind an outlet grille 8, as shown in
Next, the function and effect of the present embodiment will be described.
As shown in
In a conventional bell mouth, however, the radius of curvature of curved portion 4c is constant in the circumferential direction around center of rotation C. Thus, a conventional bell mouth does not take into account the fact that a flow path of an outlet flow varies depending on the intake conditions at each position in the circumferential direction of the bell mouth. Accordingly, an air flow cannot be flown sufficiently along curved portion 4c and flared portion 4d of bell mouth 4.
As shown in
However, as shown in
In contrast, in the present embodiment, as shown in
In this manner, in the present embodiment, radius of curvature R2 of curved portion 4c is set to be greater in the cross section of greater length L2 from center of rotation C, thereby allowing the flow to be induced significantly toward the radially outer side. Accordingly, the flow can be flown along curved portion 4c and flared portion 4d, thereby suppressing the separation and reducing the draft resistance.
The suppression of separation can in turn suppress the generation of a turbulent flow and reduce turbulent sound, thereby reducing the noise.
When front end 4e of bell mouth 4 is not connected to front panel 1a of casing 1 but protrudes forward past front panel 1a as shown in
Here, a wind speed of the flow in bell mouth 4 decreases, as the opening diameter of bell mouth 4 increases along the flow, due to diffusion of the flow. However, when front end 4e of bell mouth 4 protrudes forward past front panel 1a as shown in
When front end 4e of bell mouth 4 does not protrude forward past front panel 1a as shown in
While the present embodiment has described a configuration in which curved portion 4c and flared portion 4d are provided at the front end side of straight pipe portion 4a of bell mouth 4, flared portion 4d does not need to be provided. In this case, as shown in
An axial dimension of straight pipe portion 4a in the cross section of the portion of greater length L2 from center of rotation C to the wall portion of casing 1 as shown in
Second Embodiment
A configuration of the present embodiment is different from the configuration of the first embodiment shown in
In bell mouth 4 of the present embodiment, the radius of curvature of at least one of a curved surface portion having a greater radius of curvature and a curved surface portion having a smaller radius of curvature is maintained in the circumferential direction around center of rotation C.
As shown in
The range of angle β2 is a range within which the length between the wall portion of casing 1 and center of rotation C is relatively great as compared to that of the range of angle β1. The radius of curvature of curved portion 4c within the range of angle β1 is radius of curvature R1 shown in
As shown in
Since the configuration of the present embodiment is otherwise substantially the same as the configuration of the first embodiment described above, the same elements are designated by the same characters and description thereof will not be repeated.
The effects similar to those of the first embodiment described above can be obtained in the present embodiment. Additionally, in the present embodiment, boundary surface 4f is provided at the boundary between a part having a greater radius of curvature and a part having a smaller radius of curvature in curved portion 4c, as shown in
Third Embodiment
A configuration of the present embodiment is different from the configuration of the first embodiment shown in
As shown in
Flared portion 4d has a portion (first extending portion) Q1 located in the cross section of relatively smaller length L1 from center of rotation C (axis CL) as shown in
It should be noted that the cross section of length L1 in the present embodiment corresponds to the cross section of the portion of length L1 in
An axial dimension Lb2 of second extending portion Q2 as shown in
A tilt angle of first extending portion Q1 with respect to straight pipe portion 4a shown in
Since the configuration of the present embodiment is otherwise substantially the same as the configuration of the first embodiment described above, the same elements are designated by the same characters and description thereof will not be repeated.
Next, the function and effect of the present embodiment will be described.
As was described in the first embodiment, in the cross section of the smaller length from center of rotation C as shown in
In contrast, in the present embodiment, axial dimension Lb2 of second extending portion Q2 of flared portion 4d is set to be greater than axial dimension Lb1 of first extending portion Q1, as shown in
Fourth Embodiment
A configuration of the present embodiment is different from the configuration of the third embodiment shown in
In the present embodiment, flared portion 4d is configured to maintain at least one of a smaller axial dimension and a greater axial dimension of flared portion 4d, in the circumferential direction around center of rotation C.
As shown in
The range of angle β2 is a range within which the length between the wall portion of casing 1 and center of rotation C is relatively great as compared to that of the range of angle β1. The axial dimension of flared portion 4d within the range of angle β2 is set to be greater than the axial dimension of flared portion 4d within the range of angle β1.
As shown in
Since the configuration of the present embodiment is otherwise substantially the same as the configuration of the third embodiment described above, the same elements are designated by the same characters and description thereof will not be repeated.
The effects similar to those of the third embodiment described above can be obtained in the present embodiment. Additionally, in the present embodiment, boundary surface 4f is provided at the boundary between a part having a greater axial dimension and a part having a smaller axial dimension in flared portion 4d, as shown in
Fifth Embodiment
A configuration of the present embodiment is different from the configurations of the third and fourth embodiments in terms of the configuration of a connection between straight pipe portion 4a and flared portion 4d.
As shown in
Since the configuration of the present embodiment is otherwise substantially the same as the configuration of the third embodiment described above, the same elements are designated by the same characters and description thereof will not be repeated.
The effects similar to those of the third and fourth embodiments described above can be obtained in the present embodiment. If flared portion 4d is directly connected to straight pipe portion 4a, when the flow moves from straight pipe portion 4a to flared portion 4d, flow separation may occur at a connection 4c as indicated by an arrow Fb in
Sixth Embodiment
A configuration of the present embodiment is different from the configurations of the third to fifth embodiments in terms of the configuration of the connection between straight pipe portion 4a and flared portion 4d.
In the present embodiment, a curved portion having a rounded shape is provided at the connection between straight pipe portion 4a and flared portion 4d. Additionally, a radius of curvature of the curved portion in the cross section of the portion of the greater length from center of rotation C to the wall surface of casing 1 is set to be greater than a radius of curvature of the curved portion in the cross section of the portion of the smaller length.
Specifically, at the connection between straight pipe portion 4a and flared portion 4d in the cross section of the portion of the smaller length from center of rotation C to the wall surface of casing 1 as shown in
The aforementioned curved portion in the cross section of the portion of the smaller length from center of rotation C to the wall surface of casing 1 is, for example, a curved surface portion of the curved portion located on straight line SL1 in
The effects similar to those of the third to fifth embodiments described above can be obtained in the present embodiment. Additionally, since radius of curvature Ra of curved portion 4c varies depending on the length from center of rotation C to the wall surface of casing 1, the flow separation at curved portion 4c and flared portion 4d can be further suppressed as indicated by an arrow Rd in
Seventh Embodiment
Next, a configuration of a seventh embodiment of the present invention will be described using
Outdoor unit 10 and indoor unit 200 are coupled together by refrigerant pipes 300 and 400. A refrigerant circuit is thus formed, whereby a refrigerant circulates through outdoor unit 10 and indoor unit 200. Refrigerant pipe 300 is a gas pipe through which a gaseous refrigerant (gas refrigerant) flows. Refrigerant pipe 400 is a liquid pipe through which a liquid refrigerant (which may be a gas-liquid two-phase refrigerant) flows.
Outdoor unit 10 has, for example, a compressor 101, a four-way valve 102, outdoor heat exchanger 7, impeller 3, and a restrictor device (expansion valve) 105.
Compressor 101 compresses and discharges an introduced refrigerant. Here, compressor 101 has an inverter device and the like, and the capacity of compressor 101 (an amount of the refrigerant to be fed per unit time) can be minutely changed by arbitrarily changing operation frequency. Four-way valve 102 switches a flow of the refrigerant between cooling operation and heating operation based on an instruction from a control device (not shown).
Outdoor heat exchanger 7 exchanges heat between the refrigerant and air (outdoor air). Outdoor heat exchanger 7 functions as a condenser during the cooling operation, for example. Here, outdoor heat exchanger 7 exchanges heat between the refrigerant compressed by compressor 101 and the air, to condense and liquefy the refrigerant.
Outdoor heat exchanger 7 functions as an evaporator during the heating operation, for example. Here, outdoor heat exchanger 7 exchanges heat between the low-pressure refrigerant reduced in pressure by restrictor device 105 and the air, to evaporate and gasify the refrigerant.
Impeller 3 is provided in the vicinity of outdoor heat exchanger 7 for efficient heat exchange between the refrigerant and the air. A rotation speed of impeller 3 may be minutely changed by arbitrarily changing the operation frequency of driving source (fan motor) 5 by the inverter device.
Restrictor device 105 is provided for adjusting the pressure of the refrigerant and the like by changing the degree of opening of restrictor device 105. The refrigerant condensed by the condenser is reduced in pressure by this restrictor device 105 and expands.
Indoor unit 200 has a load side heat exchanger 201 and a load side blower 202. Load side heat exchanger 201 functions as a condenser during the heating operation, for example. Here, load side heat exchanger 201 exchanges heat between the refrigerant compressed by compressor 101 and the air, to condense and liquefy the refrigerant (or turn the refrigerant into a gas-liquid two-phase refrigerant).
Load side heat exchanger 201 functions as an evaporator during the cooling operation, for example. Here, load side heat exchanger 201 exchanges heat between the low-pressure refrigerant reduced in pressure by restrictor device 105 and the air, to evaporate and gasify the refrigerant.
Load side blower 202 is provided for adjusting an air flow subjected to heat exchange at load side heat exchanger 201. An operation speed of this load side blower 202 is determined by user settings, for example.
Next, the cooling operation and the heating operation in the refrigeration cycle device of the present embodiment will be described.
As shown in
The gas-liquid two-phase refrigerant that has flown out of outdoor unit 10 passes through liquid pipe 400 and flows into load side heat exchanger 201 within indoor unit 200. This refrigerant that has flown into load side heat exchanger 201 is evaporated and gasified into a gas refrigerant by heat exchange with the indoor air fed by load side blower 202. This gas refrigerant flows out of indoor unit 200.
The gas refrigerant that has flown out of indoor unit 200 passes through gas pipe 300 and flows into outdoor unit 10. Subsequently, the gas refrigerant passes through four-way valve 102 and is introduced into compressor 101 again. The refrigerant circulates through refrigeration cycle device 500 in this manner to perform air conditioning (cooling).
In the heating operation, four-way valve 102 is switched into a relation of connection indicated by dotted lines. The high-temperature, high-pressure gas refrigerant compressed and discharged by compressor 101 passes through four-way valve 102 and flows out of outdoor unit 10. The gas refrigerant that has flown out of outdoor unit 10 passes through gas pipe 300 and flows into load side heat exchanger 201 within indoor unit 200. The gas refrigerant that has flown into load side heat exchanger 201 is condensed and liquefied into a liquid refrigerant by heat exchange with the indoor air fed by load side blower 202, and flows out of indoor unit 200.
The liquid refrigerant that has flown out of indoor unit 200 passes through liquid pipe 400 and flows into outdoor unit 10. Subsequently, the liquid refrigerant is reduced in pressure and brought into a gas-liquid two-phase state by restrictor device 105, before flowing into outdoor heat exchanger 7. Then, the refrigerant that has flown into outdoor heat exchanger 7 is evaporated and gasified into a gas refrigerant by heat exchange with the outdoor air fed by impeller 3. This gas refrigerant passes through four-way valve 102 and is introduced into compressor 101 again. The refrigerant circulates through refrigeration cycle device 500 in this manner to perform air conditioning (heating).
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/080937 | 11/2/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/077576 | 5/11/2017 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
20110000653 | Nakagawa | Jan 2011 | A1 |
20110192186 | Kato | Aug 2011 | A1 |
20130125579 | Okazawa | May 2013 | A1 |
20140299298 | Kono | Oct 2014 | A1 |
Number | Date | Country |
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H04-251138 | Sep 1992 | JP |
H05-071768 | Mar 1993 | JP |
H10-068537 | Mar 1998 | JP |
H11-337126 | Dec 1999 | JP |
2013-096622 | May 2013 | JP |
2015-129504 | Jul 2015 | JP |
Entry |
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International Search Report of the International Searching Authority dated Feb. 2, 2016 for the corresponding international application No. PCT/JP2015/080937 (and English translation). |
Office Action dated Nov. 20, 2018 issued in corresponding JP patent application No. 2017-548541 (and English translation). |
Office Action dated May 7, 2019 issued in corresponding JP patent application No. 2017-548541 (and English translation). |
Number | Date | Country | |
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20180224135 A1 | Aug 2018 | US |