EP3196560B1

EP3196560B1 - Indoor unit for air conditioning device, and air conditioning device

Info

Publication number: EP3196560B1
Application number: EP14901479.7A
Authority: EP
Inventors: Seiji Nakashima; Takashi Ikeda; Takahide Tadokoro
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2014-09-09
Filing date: 2014-09-09
Publication date: 2020-09-09
Anticipated expiration: 2034-09-09
Also published as: JP6429887B2; EP3196560A4; EP3196560A1; WO2016038690A1; JPWO2016038690A1

Description

Technical Field

The present invention relates to an indoor unit for an air-conditioning apparatus or the like including, for example, a centrifugal fan.

Background Art

Hitherto, the following technology has been provided as a technology for controlling a flow at an air outlet portion of a fan (in particular, a technology of equalizing a wind velocity to achieve low power consumption and low noise). For example, in a centrifugal fan which includes an impeller including a plurality of air-sending fins arranged between a main plate and a side plate and is configured to send air in a direction orthogonal to or substantially orthogonal to a rotation shaft, an outer diameter of the side plate or the main plate is formed to be larger than an outer diameter of the air-sending fins of the impeller (for example, see Patent Literature 1 which discloses an indoor unit according to the preamble of claim 1).

Citation List

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. Hei 02-166323 (Page 4, Fig. 1)
Patent Literature 2: Japanese Patent Application 2007-198268 (A ) discloses a centrifugal fan and air conditioning device equipped with it.

Summary of Invention

Technical Problem

However, in the centrifugal fan disclosed in Patent Literature 1 or other disclosures, the outer diameter of the side plate or the main plate is larger than the outer diameter of the air-sending fins of the impeller. Thus, a boundary layer in the side plate and the main plate is thick, and hence an actual passage between blades is narrow. Therefore, there is a problem in that low power consumption and low noise are not achieved sufficiently.
The present invention has been made to solve the above-mentioned problem, and provides an indoor unit for an air-conditioning apparatus and other inventions achieving the low power consumption and low noise.

Solution to Problem

An air conditioning apparatus according to the present invention is set forth in claim 1.

Advantageous Effects of Invention

According to the indoor unit for an air-conditioning apparatus of one embodiment of the present invention, the air outlet is extended in a height direction at the outer periphery of the main plate, thereby being capable of equally sending air, which has flowed in through the air inlet, to an indoor heat exchanger higher than a height of the air outlet. In this case, a flow of air flowing out from the centrifugal fan is likely to extend in an inflow direction of the air, and extends along an edge with minimum difficulty. Therefore, the inflow of airflow to the heat exchanger can effectively be equalized, thereby being capable of achieving the indoor unit for an air-conditioning apparatus with low power consumption and low noise.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a perspective view of a centrifugal fan 1 of an indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 2] Fig. 2 is a top view of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 3] Fig. 3 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-Aof Fig. 2 according to Embodiment 1 of the present invention.
[Fig. 4] Fig. 4 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line B-B of Fig. 2 according to Embodiment 1 of the present invention.
[Fig. 5] Fig. 5 is a sectional view for illustrating a flow of air in a related-art indoor unit for an air-conditioning apparatus.
[Fig. 6] Fig. 6 is a sectional view for illustrating a flow of air in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 7] Fig. 7 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 2 of the present invention.
[Fig. 8] Fig. 8 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line B-B of Fig. 2 according to Embodiment 2 of the present invention.
[Fig. 9] Fig. 9 is a perspective view of the centrifugal fan 1 of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention.
[Fig. 10] Fig. 10 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 3 of the present invention.
[Fig. 11] Fig. 11 is a sectional view for illustrating a flow of air in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention.
[Fig. 12] Fig. 12 is a perspective view of the centrifugal fan 1 of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 4 of the present invention.
[Fig. 13] Fig. 13 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 5 of the present invention.
[Fig. 14] Fig. 14 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 6 of the present invention.
[Fig. 15] Fig. 15 is a view for illustrating a configuration example of an air-conditioning apparatus according to Embodiment 7 of the present invention.

Description of Embodiments

Now, with reference to the drawings, description is made of embodiments of the present invention. Note that, in Fig. 1 to Fig. 14, the same or corresponding parts are denoted by the same reference symbols, and the same applies hereinafter. Then, the modes of components described herein are merely illustrative, and are not intended to be limited to those described herein. In particular, the combination of components is not limited to the combinations in the respective embodiments, and a component described in one embodiment may be applied to another embodiment. Further, only a representative one of a plurality of blades or small blades is denoted by their reference symbol. Further, in each embodiment, description is made, with illustration in the drawings, of a case where the number of blades is seven as an example. However, an effect of the present invention can be obtained also with the number of blades other than seven. In addition, the "upper side" and the "lower side" in the following description correspond respectively to the upper side and the lower side of the drawing sheets. In addition, the sizes of components relative to one another in the drawings may differ from their relative sizes in actuality.

Embodiment 1

Fig. 1 to Fig. 4 are views for illustrating an indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Specifically, Fig. 1 is a perspective view of a centrifugal fan 1 of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Fig. 2 is a top view of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Fig. 3 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 1 of the present invention. Fig. 4 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line B-B of Fig. 2 according to Embodiment 1 of the present invention.
As illustrated in Fig. 1 to Fig. 4, the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention includes a centrifugal fan 1, a bellmouth 2, and an indoor heat exchanger 3. Herein, the indoor unit 100 for an air-conditioning apparatus of this embodiment is an indoor unit of a ceiling concealed type. The centrifugal fan 1 includes a boss 12 configured to rotate about an axial center 11, a main plate 13 coupled to the boss 12, a shroud 14 having an air inlet 141 into which gas (e.g., air) flows, and a plurality of (seven in this embodiment) blades 15 arranged between the main plate 13 and the shroud 14. Further, in the centrifugal fan 1, spaces of the blades 15 sandwiched by the main plate 13 and the shroud 14 serve as an air outlet 16. When a driving device (fan motor or other components) is mounted to the boss 12, and then the centrifugal fan 1 is rotated, air flows into (is sucked into) the air inlet 141 facing in a rotation shaft direction (hereinafter referred to as "axial direction") through the bellmouth 2. The air having flowed in flows out (is blown out) through the air outlet 16 facing in an outer peripheral direction intersecting the rotation shaft.
The bellmouth 2 is installed on a air inflow side (inlet side) of the centrifugal fan 1. The bellmouth 2 is configured to rectify air and allow the air to flow into the air inlet 141 of the centrifugal fan 1. Further, the indoor heat exchanger 3 is installed so as to surround the air outlet 16 of the centrifugal fan 1. The indoor heat exchanger 3 is configured to exchange heat between refrigerant flowing in the heat exchanger and air, to thereby cool and heat the air. Herein, in relation to the heat exchange amount and other factors, a height of the indoor heat exchanger 3 (length in the vertical direction) in the indoor unit 100 for an air-conditioning apparatus of this embodiment is set to be larger than a height of the air outlet 16 of the centrifugal fan 1 (length between the main plate 13 and the shroud 14). The air having flowed out through the air outlet 16 of the centrifugal fan 1 passes through the indoor heat exchanger 3 and flows out of the indoor unit 100 for an air-conditioning apparatus.
In the indoor unit 100 for an air-conditioning apparatus of this embodiment, at an outer peripheral edge 131 of the main plate 13 of the centrifugal fan 1, there is formed an extended portion 132 extending toward the main plate 13 side in the axial direction (inflow direction of air flowing into the centrifugal fan 1, which is hereinafter referred to as "axial main plate side") to increase the size of the air outlet 16 in an opening height direction. Herein, the extended portion 132 is formed to have an arcuate shape (including a case of a substantially arcuate shape, which is hereinafter referred to as "substantially arcuate shape") in a sectional surface including the rotation shaft. Further, as is clear from the difference in the extended portion 132 between Fig. 3 and Fig. 4, the extended portion 132 is formed to have a curvature radius larger at blade portions 152, which are first portions at which the main plate 13 and the blades 15 are connected, than portions between blades 151, which are second portions.
Fig. 5 is a sectional view for illustrating a flow of air in a related-art indoor unit for an air-conditioning apparatus. Further, Fig. 6 is a sectional view for illustrating a flow of air in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Herein, for clarification of correspondence, the reference symbols which are the same as those denoting the members of the indoor unit 100 for an air-conditioning apparatus of this embodiment are given in Fig. 5. With reference to Fig. 1, Fig. 5, and Fig. 6, description is made of an effect which can be obtained by the configuration of the indoor unit 100 for an air-conditioning apparatus of this embodiment.
As described above, in the indoor unit 100 for an air-conditioning apparatus, air having flowed out through the air outlet 16 of the centrifugal fan 1 flows into the indoor heat exchanger 3. In this case, a height of the indoor heat exchanger 3 and a height of the air outlet 16 are different. Thus, as illustrated in Fig. 5, the flow into the indoor heat exchanger 3 is uneven in the related-art indoor unit 100 for an air-conditioning apparatus. For example, less air flows into a region which corresponds to a side being a top surface (lower side in Fig. 5) at the time of installation of the indoor unit 100 for an air-conditioning apparatus.
In contrast, as illustrated in Fig. 6, the indoor unit 100 for an air-conditioning apparatus of this embodiment has, at the outer peripheral edge 131 of the main plate 13, the extended portion 132 having the substantially arcuate shape, which causes the air outlet 16 to extend toward the axial main plate side. Thus, the air flowing out from the centrifugal fan 1 is likely to extend toward the top surface side.
Further, as illustrated in Fig. 1 and Fig. 6, a flow of the air flowing out from the centrifugal fan 1 has a large outflow velocity at the blade portions 152 giving work to airflow, and has a small outflow velocity at portions between blades 151 of the blade portions 152. Thus, the extended portion 132 having the substantially arcuate shape is formed to have a large curvature ratio at the blade portions 152 having a large outflow velocity, and is formed to have a small curvature ratio at the portions between blades 151 having a small outflow velocity. Then, air is caused to extend, with minimum difficulty, toward the axial main plate side along the extended portion 132 having the substantially arcuate shape at the outer peripheral edge 131 of the main plate 13. Therefore, the inflow of air to the indoor heat exchanger 3 can effectively be equalized. Accordingly, the indoor unit 100 for an air-conditioning apparatus can be configured with low power consumption and low noise.

Embodiment 2

In order to further achieve lower power consumption and lower noise in the indoor unit 100 for an air-conditioning apparatus, it is preferred that the indoor unit 100 for an air-conditioning apparatus of this embodiment have the following configuration. Fig. 7 and Fig. 8 are views for illustrating the indoor unit 100 for an air-conditioning apparatus according to Embodiment 2 of the present invention. Specifically, Fig. 7 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 2 of the present invention. Further, Fig. 8 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line B-B of Fig. 2 according to Embodiment 2 of the present invention.
With regard to the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 2, matters which are different from those of Embodiment 1 are described. The indoor unit 100 for an air-conditioning apparatus of this embodiment is configured such that a tangential line on the outer peripheral edge 131 at the extended portion 132, which has the substantially arcuate shape and extends toward the axial main plate side at the outer peripheral edge 131 of the main plate 13 of the centrifugal fan 1, passes through a lower end 31 of the indoor heat exchanger 3 at a position where the outer peripheral edge 131 of the centrifugal fan 1 and the indoor heat exchanger 3 are closest to each other in distance therebeween.
With the above-mentioned configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 2, the outflow from the centrifugal fan 1 extending along the extended portion 132 having the substantially arcuate shape extending toward the axial main plate side at the outer peripheral edge 131 of the main plate 13 extends at an optimum extending angle. Thus, the outflow flows into the indoor heat exchanger 3 with moderate quantity. Therefore, the inflow of the airflow into the indoor heat exchanger 3 can be equalized more effectively, thereby being capable of further achieving the indoor unit 100 for an air-conditioning apparatus with low power consumption and low noise.

Embodiment 3

In order to further achieve lower power consumption and lower noise in the indoor unit 100 for an air-conditioning apparatus, it is preferred that the indoor unit 100 for an air-conditioning apparatus of this embodiment have the following configuration. Fig. 9 and Fig. 10 are views for illustrating the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention. Specifically, Fig. 9 is a perspective view of the centrifugal fan 1 of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention. Further, Fig. 10 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 3 of the present invention.
With regard to the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention, matters which are different from those of Embodiment 1 and Embodiment 2 are described. As illustrated in Fig. 9 and Fig. 10, the indoor unit 100 for an air-conditioning apparatus of this embodiment includes small blades 17 arranged on an upstream surface of the shroud 14 of the centrifugal fan 1.
Fig. 11 is a sectional view for illustrating a flow of air in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3 of the present invention. With reference to Fig. 11, description is made of an effect which can be obtained by the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 3.
As illustrated in Fig. 9 to Fig. 11, with the small blades 17 arranged on the upstream surface of the shroud 14 of the centrifugal fan 1, a shroud-neighboring vortex 4 generated in a space formed among the shroud 14, the bellmouth 2, and the indoor heat exchanger 3 can be strong. Thus, an airflow inducing effect exerted by the action of the strong shroud-neighboring vortex 4 may cause the air flowing out from the centrifugal fan 1 to be likely to extend toward the bellmouth 2 side in the axial direction (axial bellmouth side). Therefore, the inflow of the airflow into the indoor heat exchanger 3 can be equalized more effectively, thereby being capable of achieving the indoor unit 100 for an air-conditioning apparatus with low power consumption and low noise.

Embodiment 4

In order to further achieve lower power consumption and lower noise in the indoor unit 100 for an air-conditioning apparatus, it is preferred that the indoor unit 100 for an air-conditioning apparatus have the following configuration. Fig. 12 is a perspective view of the centrifugal fan 1 of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 4 of the present invention.
With regard to the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 4 of the present invention, matters which are different from those of Embodiment 1 to Embodiment 3 are described. Although particular description is not made in Embodiment 3, in the indoor unit 100 for an air-conditioning apparatus, the number of the small blades 17 arranged on the upstream surface of the shroud 14 of the centrifugal fan 1 is the same as the number of the plurality of blades 15 arranged between the main plate 13 and the shroud 14. Further, the small blades 17 are arranged at the same positions as the blades 15 when viewed in the axial direction.
Effects which can be obtained with the above-mentioned configuration are described. A flow of air flowing out from the centrifugal fan 1 has a large outflow velocity at the blade portions 152 giving work to airflow, and has a small outflow velocity at the portions between blades 151 of the blade portions 152. Further, the strong shroud-neighboring vortex 4 is generated at each of small blade portions 172 being spaces near the small blades 17 arranged on the upstream surface of the shroud 14. Meanwhile, a weak shroud-neighboring vortex 4 is generated at each of between-small-blades portions 171 being spaces of the small blades 17.
As in this embodiment, when the small blades 17 are arranged on the upstream surface of the shroud 14 of the centrifugal fan 1 with the same number and the same positions as the plurality of blades 15 arranged between the main plate 13 and the shroud 14, a relatively stronger shroud-neighboring vortex 4 is generated at the blade portions 152 having a large outflow velocity to extend the outflow having a large flow velocity toward the axial shroud side with an inducing effect. Further, a relatively weaker shroud-neighboring vortex 4 is generated at the portions between blades 151 having a small outflow velocity to extend the outflow having a small flow velocity toward the axial shroud side with the inducing effect. Therefore, the inducing effect having a strength corresponding to a magnitude of the outflow velocity can be exerted. Thus, the inflow of the airflow into the indoor heat exchanger 3 can more effectively be equalized, thereby being capable of achieving the indoor unit 100 for an air-conditioning apparatus with low power consumption and low noise.

Embodiment 5

In order to further achieve lower power consumption and lower noise in the indoor unit 100 for an air-conditioning apparatus, it is preferred that the indoor unit 100 for an air-conditioning apparatus have the following configuration. Fig. 13 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 5 of the present invention.
With regard to the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 5 of the present invention, matters which are different from those of Embodiment 1 to Embodiment 4 are described. As illustrated in Fig. 13, with regard to the small blades 17 arranged on the upstream surface of the shroud 14 of the centrifugal fan 1, an axial height from a shroud outer peripheral edge 142 to a small blade outer peripheral upper edge 173 is h, and an axial height from the shroud outer peripheral edge 142 to the bellmouth 2 is H. In this case, in this embodiment, the indoor unit 100 for an air-conditioning apparatus is configured so that h is one-half of or less than H.
With the above-mentioned configuration, in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 5, a magnitude of the shroud-neighboring vortex 4 generated by the small blades 17 is not excessively large. Thus, interference with the bellmouth 2 is prevented. Therefore, while a flow loss is suppressed to be minimum, the flow of the air flowing out from the centrifugal fan 1 can effectively be extended toward the axial shroud side by the inducing effect. Thus, the inflow of the airflow to the indoor heat exchanger 3 can be equalized, thereby being capable of achieving the indoor unit 100 for an air-conditioning apparatus with low power consumption and low noise.

Embodiment 6

In order to further achieve lower power consumption and lower noise in the indoor unit 100 for an air-conditioning apparatus, it is preferred that the indoor unit 100 for an air-conditioning apparatus have the following configuration. Fig. 14 is a sectional view of the indoor unit 100 for an air-conditioning apparatus taken along the line A-A of Fig. 2 according to Embodiment 6 of the present invention.
With regard to the configuration of the indoor unit 100 for an air-conditioning apparatus according to Embodiment 6 of the present invention, matters which are different from those of Embodiment 1 to Embodiment 5 are described. As illustrated in Fig. 14, a radial distance at a position where the air outlet 16 at the outer peripheral edge 131 of the centrifugal fan 1 and the indoor heat exchanger 3 are closest to each other is L. Further, with regard to an axial distance between the shroud outer peripheral edge 142 of the centrifugal fan 1 and an upper end 32 of the heat exchanger and an axial distance between the outer peripheral edge 131 of the main plate 13 of the centrifugal fan 1 and a lower end 31 of the heat exchanger, a smaller distance is L1, and a larger distance is L2. In this case, the indoor unit 100 for an air-conditioning apparatus of this embodiment is configured to satisfy L1 <L<L2. Herein, in Fig. 14, illustration is made of the case where the axial distance between the outer peripheral edge 131 of the main plate 13 of the centrifugal fan 1 and the lower end 31 of the heat exchanger is L1, and where the axial distance between the shroud outer peripheral edge 142 of the centrifugal fan 1 and the upper end 32 of the heat exchanger is L2. However, the present invention is not limited thereto.
With the above-mentioned configuration, in the indoor unit 100 for an air-conditioning apparatus according to Embodiment 6, a distance between the air outlet 16 at the outer peripheral edge 131 of the centrifugal fan 1 and the indoor heat exchanger 3 can appropriately be maintained. Further, the extended portion 132 having the substantially arcuate shape extending toward the axial main plate side is formed at the outer peripheral edge 131 of the main plate 13. The curvature ratio of the extended portion 132 having the substantially arcuate shape is set to be large at the blade portion 152 having a large outflow velocity and set to be small at the portion between blades 151 having a small outflow velocity. Further, the outflow of the centrifugal fan 1 extended with the small blades 17 arranged on the upstream surface of the shroud 14 of the centrifugal fan 1 most effectively and equally flows into the indoor heat exchanger 3. Therefore, the indoor unit 100 for an air-conditioning apparatus with low power consumption and low noise can be achieved.

Embodiment 7

Fig. 15 is a view for illustrating a configuration example of an air-conditioning apparatus according to Embodiment 7 of the present invention. In the air-conditioning apparatus of Fig. 15, an outdoor unit 200 and the indoor unit 100 are connected to each other by pipes including a gas refrigerant pipe 300 and a liquid refrigerant pipe 400. The outdoor unit 200 includes a compressor 201, a four-way valve 202, an outdoor heat exchanger 203, an expansion valve 204, and an outdoor air-sending device 205. Further, the indoor unit 100 for an air-conditioning apparatus includes the indoor heat exchanger 3.
The compressor 201 is configured to compress and discharge sucked refrigerant. Note that, the compressor 201 is not particularly limited, but may include, for example, an inverter circuit so that an operating frequency thereof is arbitrarily changed, thereby being capable of changing a capacity of the compressor 201 (amount of refrigerant sent per unit time). The four-way valve 202 is a valve configured to switch flow of the refrigerant during the cooling operation and flow of the refrigerant during the heating operation to each other, for example.
The outdoor heat exchanger 203 is configured to exchange heat between the refrigerant and the air (outside air). Specifically, the outdoor heat exchanger 203 functions as an evaporator during the heating operation so as to evaporate and gasify the refrigerant, and functions as a condenser during the cooling operation so as to condense and liquefy the refrigerant. Further, the outdoor air-sending device 205 is configured to send the air into the outdoor heat exchanger 203. The expansion valve 204, e.g., an expansion device (flow rate control unit) is configured to decompress and extend the refrigerant. For example, when the expansion valve 204 is constructed by an electronic expansion valve, an opening degree thereof is controlled in response to instructions from a controller (not shown), for example.
Further, as described above, the indoor heat exchanger 3 is configured to exchange heat between the gas (for example, air to be air-conditioned) and the refrigerant. The indoor heat exchanger 3 functions as the condenser during the heating operation so as to condense and liquefy the refrigerant, and functions as the evaporator during the cooling operation so as to evaporate and gasify the refrigerant.
As described above, for example, the centrifugal fan 1 sends air, which is to be air-conditioned, into the indoor heat exchanger 3. The centrifugal fan 1 of this embodiment has the extended portion 132 formed on the main plate 13.
Therefore, according to the air-conditioning apparatus of Embodiment 7, through use of the indoor unit 100 for an air-conditioning apparatus described in Embodiment 1 to Embodiment 6, the inflow of the airflow to the indoor heat exchanger 3 can effectively be equalized. Thus, the low power consumption and low noise can be achieved in the apparatus as a whole.

Industrial Applicability

In Embodiment 7, description is made of the air-conditioning apparatus. However, the indoor unit of Embodiment 1 to Embodiment 3 can be used for other refrigeration cycle apparatus, e.g., a refrigerating apparatus.

Reference Signs List

1 centrifugal fan 2 bellmouth 3 indoor heat exchanger 4 shroud-neighboring vortex 11 axial center 12 boss 13 main plate 14 shroud 15 blade 16 air outlet 17 small blade 31 lower end 32 upper end 100 indoor unit for air-conditioning apparatus 131 outer peripheral edge 132 extended portion 141 air inlet 142 shroud outer peripheral edge 151 portion between blades (second portion) 152 portion between blades (first portion) 171 between-small-blades portion 172 small blade portion 173 small blade outer peripheral upper edge 200 outdoor unit 201 compressor 202 four-way valve 203 outdoor heat exchanger 204 expansion valve 205 outdoor air-sending device 300 gas refrigerant pipe 400 liquid refrigerant pipe

Claims

An indoor unit for an air-conditioning apparatus,
the indoor unit comprising:
a centrifugal fan (1) including
a main plate (13) fixed to a rotation shaft;

a shroud (14) opposed to the main plate (13) and having an air inlet (141) into which air can flow; and

a plurality of blades (15) arranged between the main plate (13) and the shroud (14), and respectively connected to first portions of the main plate (13); and

an air outlet (16) formed at second portions of the main plate (13) between the blades (15) and through which air can be flowed out, wherein spaces of the blades (15) sandwiched by the main plate (13) and the shroud (14) serve as the air outlet (16),

the main plate (13) having an extended portion (132) formed at an outer peripheral edge (131) thereof, the extended portion (132) extending in a direction to extend an opening height of the air outlet (16), the extended portion (132) being formed to have an arcuate shape in a sectional surface including the rotation shaft, the arcuate shape having a curvature ratio; characterized in that

the curvature ratio of the arcuate shape of the extended portion (132) is configured to be larger at the first portions than at the second portions.
The indoor unit for an air-conditioning apparatus of claim 1, further comprising an indoor heat exchanger (3) having a height higher than the opening height, the indoor heat exchanger being arranged so as to surround the air outlet, and configured such that a tangential line to the arcuate shape of the extended portion (132) of passes through a lower end of the indoor heat exchanger (3) at a position where the outer peripheral edge (131) and the indoor heat exchanger (3) are closest to each other.
The indoor unit for an air-conditioning apparatus of claim 1 or 2, wherein the centrifugal fan (1) comprises small blades (172) on an upstream surface of the shroud (14).
The indoor unit for an air-conditioning apparatus of claim 3, wherein a number of the small blades (172) is the same as a number of the blades (15), and the small blades (172) are arranged at the same positions as the blades when viewed in the rotation shaft direction.
The indoor unit for an air-conditioning apparatus of claim 3 or 4, wherein a height of the small blades (172) is one-half of or less than a distance between an outer peripheral edge of the shroud (14) and a bellmouth (2) arranged on an air inflow side of the centrifugal fan (1) in the rotation shaft direction.
The indoor unit for an air-conditioning apparatus of any one of claims 1 to 4, wherein, when a radial distance at a position where an outer peripheral edge of the centrifugal fan (1) and the indoor heat exchanger (3) are closest to each other is L, and, with regard to an axial distance between a shroud (14) outer peripheral edge of the centrifugal fan (1) and an upper edge of a heat exchanger (3) and an axial distance between an edge of the outer peripheral portion of the main plate (13) of the centrifugal fan (1) and a lower end of the heat exchanger (3), a shorter distance is L1, and a longer distance is L2, a relationship of L1 <L<L2 is satisfied.
An air-conditioning apparatus, configured to perform air-conditioning, comprising:
the indoor unit for an air-conditioning apparatus (100) of any one of claims 1 to 6; and

an outdoor unit (200).