Impeller, centrifugal blower, indoor unit, air conditioning device, ventilation fan, electric vacuum cleaner, and hand dryer

Abstract

In centrifugal blowers, tilting a main plate toward a side plate can mitigate worsening noise, but the blowing width between the main plate and the side plate is reduced. In this case, the volume of air blown from the centrifugal blower decreases, and the efficiency of the centrifugal blower suffers. The objective of the present disclosure is to provide an impeller that can be used to achieve higher efficiency. The impeller comprises: a main plate rotationally driven about an axis; an annular side plate disposed opposite the main plate in the axial direction; a plurality of blades disposed between the main plate and the side plate; and an airflow guide portion provided on the main plate and having a first inclined portion formed so that the axial distance between the main plate and the side plate widens proceeding toward the inner-diameter side of the main plate, wherein the airflow guide portion is provided farther on the inner-diameter side than an outermost peripheral edge portion of the main plate.

Description

Impellers, centrifugal fans, indoor units, air conditioners, ventilation fans, electric vacuum cleaners and hand dryers

[0001] The present disclosure relates to an impeller, a centrifugal blower, an indoor unit, an air conditioner, a ventilation fan, an electric vacuum cleaner, and a hand dryer.

[0002] In recent years, there has been a strong demand for low noise and high efficiency centrifugal fans in the air conditioning system, where there is intense competition to achieve both low noise and high efficiency. To reduce noise in centrifugal fans, it is effective to make the air velocity distribution uniform between the main plate and side plate of the impeller.

[0003] For example, in the case of Patent Document 1, the main plate is tilted toward the side plate to guide the airflow toward the side plate, preventing the intake airflow from concentrating toward the main plate and causing a local increase in wind speed on the main plate side, thereby suppressing noise deterioration.

[0004] Japanese Utility Model Application Laid-Open Publication No. 1-130100

[0005] However, in the fan described in Patent Document 1, the width of the airflow between the main plate and the side plate is reduced by tilting the main plate toward the side plate, which results in a reduction in the volume of air blown from the centrifugal fan and a decrease in the efficiency of the centrifugal fan.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an impeller that can achieve high efficiency.

[0007] The impeller according to the present disclosure comprises a main plate that is driven to rotate around an axis, an annular side plate that is arranged axially opposite the main plate, a plurality of blades that are arranged between the main plate and the side plate, and an airflow guiding portion that is provided on the main plate and has a first inclined portion that is formed so that the axial distance between the main plate and the side plate becomes wider toward the inner diameter side of the main plate, and the airflow guiding portion is provided on the inner diameter side of the outermost peripheral end of the main plate.

[0008] According to the present disclosure, high efficiency can be achieved.

[0009] 1. A top view showing the structure of a centrifugal blower according to embodiment 1. A perspective view showing the structure of an impeller according to embodiment 1. A cross-sectional view taken along line B-B in FIG. 3, which is the top view showing the structure of the impeller according to embodiment 1. A cross-sectional view showing the air flow in the centrifugal blower according to embodiment 1. A cross-sectional view showing the dimensional relationship of the impeller according to embodiment 1. A cross-sectional view showing the structure of an impeller according to embodiment 2. A cross-sectional view showing the air flow in the centrifugal blower according to embodiment 2. An airflow distribution diagram showing the airflow distribution when θ1 of the impeller according to embodiment 2 is 45 degrees. An airflow distribution diagram showing the airflow distribution when θ1 of the impeller according to embodiment 2 is 60 degrees. A perspective view showing the structure of an impeller according to embodiment 3. A partially enlarged view showing the impeller in FIG. 11. An internal configuration diagram of an indoor unit according to embodiment 4. A diagram schematically showing the configuration of an air conditioning apparatus according to embodiment 5. A refrigerant circuit diagram showing the flow of refrigerant during cooling operation in an air conditioning apparatus according to embodiment 5. A refrigerant circuit diagram showing the flow of refrigerant during heating operation in an air conditioning apparatus according to embodiment 5.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, in the following drawings, including FIG. 1, the dimensional relationships between components may differ from those in actuality. Furthermore, the configurations of components shown in the entire specification are merely illustrative and are not limited to these descriptions. The direction along the circumference of a circle centered on the axis C1, which is the center of rotation of the impeller 2, is referred to as the "circumferential direction," the direction parallel to the axis C1 is referred to as the "axial direction," and the direction perpendicular to the axis C1 is referred to as the "radial direction." The drawings also show an x-y-z Cartesian coordinate system to facilitate mutual understanding of the drawings. The z-axis is a coordinate axis parallel to the axis C1 of the impeller 2. The y-axis is a coordinate axis perpendicular to the z-axis. The x-axis is a coordinate axis perpendicular to both the y-axis and the z-axis.

[0011] Embodiment 1. <Configuration and Operation of Centrifugal Fan According to Embodiment 1> Fig. 1 is a top view showing the structure of a centrifugal fan 1 according to Embodiment 1. Centrifugal fan 1 according to Embodiment 1 includes an impeller 2 housed in a casing 3. Casing 3 is formed with an intake port 4 for drawing in air and an outlet port 5 for blowing out air.

[0012] Fig. 2 is a perspective view showing the structure of the impeller 2 according to the first embodiment. Fig. 3 is a top view showing the structure of the impeller 2 according to the first embodiment. Fig. 4 is a cross-sectional view taken along line B-B in Fig. 3. As shown in Figs. 2-4, the impeller 2 according to the first embodiment includes a main plate 10 which is a rotating body, an annular side plate 40 which faces the main plate 10, and blades 60 which are provided between the main plate 10 and the side plate 40.

[0013] The main plate 10 is a disk-shaped rotating body that rotates around an axis C1. The main plate 10 has a boss (not shown) provided in the center and an airflow guide portion 20. The boss is a portion to which a shaft of a motor (not shown) is connected and fixed. When the motor is driven, the main plate 10 rotates around the axis C1. The airflow guide portion 20 will be described later.

[0014] The side plate 40 is an annular rotating body disposed opposite the main plate 10. As shown in Fig. 2, an opening for allowing air to flow in the axial direction is provided on the inner diameter side of the side plate 40. This opening will be referred to as an "inlet 41" hereinafter.

[0015] The blades 60 are disposed between the main plate 10 and the side plate 40, and are arranged in the circumferential direction centered on the axis C1 of the main plate 10. One end of each blade 60 is connected to the main plate 10, and a portion of the other end of each blade 60 is connected to the side plate 40. Between the multiple blades 60, there are outlets 61 that blow out air in a direction perpendicular to the axial direction.

[0016] 4, the airflow guide section 20 is provided on the main plate 10 and has a first inclined section 21. The first inclined section 21 is an inclined section formed so that the distance between the main plate 10 and the side plate 40 in the axial direction (i.e., the z-axis direction) becomes wider toward the inner diameter side of the main plate 10 (i.e., the x-axis direction).

[0017] The airflow guide portion 20 is provided on the inner diameter side of the outermost peripheral end portion 12 of the main plate 10. The outermost peripheral end portion 12 is the end portion of the main plate 10 that faces the outermost peripheral side.

[0018] Next, a description will be given of the operation of the centrifugal blower 1 according to the present embodiment 1. Fig. 5 is a cross-sectional view showing the flow of air in the centrifugal blower 1 according to the present embodiment 1. In Fig. 5, arrows A1, A2, and A3 indicate the direction of the air flow.

[0019] 4, when a motor (not shown) is driven, the torque of the motor shaft is transmitted to the impeller 2, causing the impeller 2 to rotate. As the impeller 2 rotates, air is drawn into the impeller 2 from the inlet 41 and blown out from the outlet 61, which is located in a direction substantially perpendicular to the axis C1 of the impeller 2. This allows the centrifugal fan 1 to function.

[0020] Furthermore, the impeller 2 according to the first embodiment has an airflow guide portion 20 on the main plate 10. As shown in Fig. 5 , air drawn in through the inlet 41 flows from the side plate 40 side toward the main plate 10 side. Here, the air drawn in through the inlet 41 tends to have a larger air volume the closer it is to the main plate 10, as indicated by arrow A1, and a smaller air volume the closer it is to the side plate 40, as indicated by arrow A2.

[0021] The airflow guiding section 20 has a first inclined section 21. The air flowing along the main board 10 side in the direction of arrow A1 collides with the airflow guiding section 20, and the air is guided along the first inclined section 21 toward the side board 40 side. This makes it possible to suppress a local increase in wind speed on the main board 10 side and to homogenize the wind speed distribution of the air blown out from the outlet 61 as shown by arrow A3. By homogenizing the wind speed distribution of the air blown out from the outlet 61, it is possible to reduce noise generated by the air blown out from the outlet 61.

[0022] Furthermore, the airflow guide section 20 is provided on the inner diameter side of the outermost peripheral end 12 of the main plate 10. This causes the air blown out along the first inclined section 21 toward the outer diameter side of the first inclined section 21 to be blown out toward the main plate 10. This prevents the axial distance between the main plate 10 and the side plate 40 at the outlet 61 (hereinafter referred to as the "outlet width W") from being reduced, making it possible to suppress a decrease in the volume of air blown out from the outlet 61.

[0023] Furthermore, by arranging the airflow guide section 20 on the inner diameter side of the outlet 61, the reduction in the outlet width W can be suppressed, and the effect of suppressing a decrease in the volume of air blown out from the outlet 61 can be further enhanced.

[0024] It is also desirable that the first inclined portion 21 be a flat surface, which can suppress a reduction in the outflow width W and further enhance the effect of suppressing a decrease in the volume of air blown out from the outflow port 61. Note that the first inclined portion 21 is not limited to a flat surface, and may be, for example, a curved surface.

[0025] Fig. 6 is a cross-sectional view showing the dimensional relationship of the impeller 2 according to the first embodiment. As shown in Fig. 6, when the axial distance between the main plate 10 and the side plate 40 is L1 and the maximum length of the airflow guide portion 20 in the axial direction from the main plate 10 is L2, it is desirable that 0 < L2 / L1 ≦ 0.5 be satisfied. This is because when 0 < L2 / L1 ≦ 0.5 is satisfied, it is possible to suppress a decrease in the volume of air blown out from the outlet 61 while suppressing a local increase in wind speed on the main plate 10 side.

[0026] 6, if the shortest distance from the outermost peripheral end 12 of the main plate 10 to the airflow guiding portion 20 is L3, it is desirable that L2≧L3 be satisfied. This makes it possible to suppress a decrease in the volume of air blown out from the outlet 61.

[0027] <Effects of the Centrifugal Fan According to the First Embodiment> The centrifugal fan 1 according to the first embodiment can suppress a reduction in the outflow width W, thereby increasing the volume of air blown out from the outflow port 61 and improving the efficiency of the centrifugal fan 1. Furthermore, the centrifugal fan 1 according to the first embodiment is provided with an airflow guiding section 20 having a first inclined portion 21 on the main plate 10. Air flows along the first inclined portion 21 of the airflow guiding section 20, thereby guiding the air toward the side plate 40. If the airflow guiding section 20 were not provided, the air drawn in from the inflow port 41 would concentrate toward the main plate 10 rather than the side plate 40. In the centrifugal fan 1 according to the first embodiment, the provision of the airflow guiding section 20 can suppress a local increase in wind speed at the main plate 10, thereby suppressing an increase in noise.

[0028] Embodiment 2. <Configuration and Operation of Centrifugal Fan According to Embodiment 2> A centrifugal fan 1a according to Embodiment 2 will be described. Note that a description of matters common to Embodiment 1 will be omitted, and only matters different from Embodiment 1 will be described.

[0029] Figure 7 is a cross-sectional view showing the structure of an impeller 2a according to the second embodiment. As shown in Figure 7, the impeller 2a according to the second embodiment has a second inclined portion 22 in the airflow guide portion 20. The second inclined portion 22 is formed so that the distance in the axial direction of the main plate 10 and the side plate 40 (i.e., the z direction) becomes wider from the first inclined portion 21 toward the outer diameter side of the main plate 10 (i.e., the x direction). In other words, the second inclined portion 22 is provided closer to the outer diameter side of the main plate 10 than the first inclined portion 21. Furthermore, a connecting portion 23 is provided that connects the first inclined portion 21 and the second inclined portion 22.

[0030] 8 is a cross-sectional view showing the air flow in the centrifugal blower 1a according to the second embodiment. The air on the main plate 10 side collides with the airflow guide portion 20, and is guided along the first inclined portion 21 toward the side plate 40 side. Furthermore, the air guided toward the side plate 40 side is guided toward the main plate 10 along the connecting portion 23 and the second inclined portion 22. This makes it possible to suppress separation of the airflow when the air along the first inclined portion 21 is blown toward the side plate 40 side, and to suppress a decrease in the volume of air blown out from the outlet 61.

[0031] Although the shape of the connection portion 23 is not particularly limited, it is desirable for the connection portion 23 to have a circular chamfered portion. By making the shape of the connection portion 23 smooth and circular, it is possible to enhance the effect of suppressing separation of the airflow when air flowing along the first inclined portion 21 is blown toward the side plate 40, and to enhance the effect of suppressing a decrease in the volume of air blown out from the outlet 61. Although the radius of the chamfered portion is not particularly limited, by making the radius 1 mm or more, the chamfered portion does not become sharp, and the effect of suppressing separation of the airflow can be enhanced.

[0032] Moreover, it is desirable that the angle θ1 [degrees] formed between the main plate 10 and the first inclined portion 21 is configured so as to satisfy the relationship 0<θ1≦45. The reason for this will be explained below.

[0033] FIG. 9 is an airflow distribution diagram showing the airflow distribution of the impeller 2a according to the second embodiment when θ1 is 45 degrees. FIG. 10 is an airflow distribution diagram showing the airflow distribution of the impeller 2a according to the second embodiment when θ1 is 60 degrees. As shown in FIG. 9 , when θ1 = 45 degrees, air flows along the second inclined portion 22, so air does not separate on the outer diameter side of the connecting portion 23, and a decrease in the volume of air blown out from the outlet 61 can be suppressed. On the other hand, as shown in FIG. 10 , when θ1 = 60 degrees, air flows along the second inclined portion 22 and separates midway, resulting in a decrease in the volume of air blown out from the outlet 61. In this way, by reducing θ1, it is possible to suppress the separation of air on the outer diameter side of the connecting portion 23.

[0034] As described above, by making θ1 0<θ1≦45, the effect of suppressing the air flowing along the airflow guide portion 20 from separating on the outer diameter side of the connection portion 23 can be enhanced.

[0035] <Effects of the Centrifugal Fan According to the Second Embodiment> In the centrifugal fan 1a according to the second embodiment, when the air along the first inclined portion 21 is blown out toward the side plate 40, the air flows along the second inclined portion 22 toward the main plate 10, thereby suppressing separation of the airflow. This allows the air blown out from the outlet 61 to be kept appropriate, thereby improving the efficiency of the centrifugal fan 1a without increasing noise.

[0036] Embodiment 3. <Configuration of a centrifugal fan according to embodiment 3> A centrifugal fan 1b according to embodiment 3 will be described. Note that a description of matters common to embodiment 1 will be omitted, and only matters different from embodiment 1 will be described.

[0037] FIG. 11 is a perspective view showing the structure of an impeller 2b according to the third embodiment. FIG. 12 is a partially enlarged view showing the impeller 2b in FIG. 11. As shown in FIGS. 11-12, the impeller 2b according to the third embodiment has a slit 24 in the airflow guiding portion 20. The airflow guiding portion 20 may have at least one slit 24. More preferably, as shown in FIGS. 11-12, the airflow guiding portion 20 between the blades 60 has at least two slits 24. By having at least two slits 24, when the impeller 2b is molded from resin by injection molding, the effect of promoting heat dissipation from the airflow guiding portion 20 to the outside air is enhanced, and the effect of suppressing the occurrence of sink marks in the airflow guiding portion 20 is enhanced.

[0038] <Effects of the Centrifugal Fan According to the Third Embodiment> Impeller 2b according to the third embodiment has at least one slit 24 in airflow guiding section 20. When impeller 2b is molded from resin by injection molding during the production process of impeller 2b, this slit 24 can promote heat dissipation from airflow guiding section 20 to the outside air. That is, impeller 2b according to the third embodiment can suppress the occurrence of sink marks in airflow guiding section 20, thereby suppressing the occurrence of dents on the surface of airflow guiding section 20. This can suppress a decrease in the amount of air blown from centrifugal fan 1b, thereby achieving high efficiency of centrifugal fan 1b.

[0039] The centrifugal blowers 1, 1a, and 1b according to the present embodiments 1-3 have been described as sirocco fans as a form for generating airflow during operation, but any blower that blows air in a direction approximately perpendicular to the direction of the rotation axis of the blower may be used, such as a turbofan or a radial fan.

[0040] Although the centrifugal fans 1, 1a, and 1b according to the present embodiments 1 to 3 have been described as being of a double-inlet type that draws air from two directions, they may also be of a single-inlet type that draws air from one direction.

[0041] Fourth Embodiment An indoor unit 110 according to a fourth embodiment will now be described in detail with reference to the drawings.

[0042] <Configuration and Operation of Indoor Unit> Fig. 13 is a diagram showing the internal configuration of the indoor unit 110 according to Embodiment 4. The indoor unit 110 may be a floor-standing type, a ceiling-embedded type, or the like.

[0043] The indoor unit 110 has an indoor unit housing 120, any one of the centrifugal fans 1, 1a, and 1b according to embodiments 1-3, and an indoor heat exchanger 130. The indoor unit housing 120 may be formed in a rectangular parallelepiped shape, a cylindrical shape, a square pillar shape, or the like. Also, although FIG. 13 shows one centrifugal fan 1, 1a, and 1b, the indoor unit 110 may have a plurality of centrifugal fans 1, 1a, and 1b.

[0044] The indoor unit housing 120 has an indoor unit inlet 123 formed on an upper surface 121 and an indoor unit outlet 124 formed on a lower surface 122 .

[0045] The indoor heat exchanger 130 functions as an evaporator during cooling operation and as a condenser during heating operation. The cooling operation and heating operation are switched by switching the flow path using a four-way valve (not shown).

[0046] The operation of the indoor unit 110 according to Embodiment 4 will now be described. When a motor (not shown) rotates, the centrifugal fans 1, 1a, and 1b are rotated, and air outside the indoor unit 110 is drawn into the indoor unit housing 120 through the indoor unit inlet 123 of the indoor unit housing 120. The air drawn into the indoor unit housing 120 passes through the indoor heat exchanger 130. The air passing through the indoor heat exchanger 130 exchanges heat with a refrigerant (not shown) flowing inside the indoor heat exchanger 130, and the temperature is adjusted.

[0047] The air that has passed through the indoor heat exchanger 130 is drawn into the centrifugal fans 1, 1a, and 1b. The air drawn into the centrifugal fans 1, 1a, and 1b is blown out toward the air outlets 5 formed in the casings 3 of the centrifugal fans 1, 1a, and 1b. The air blown out from the air outlets 5 is blown out from the indoor unit 110 through the indoor unit air outlets 124 of the indoor unit housing 120.

[0048] <Effects of the indoor unit> The indoor unit 110 according to Embodiment 4 includes any one of the centrifugal fans 1, 1a, and 1b according to Embodiments 1 to 3, and therefore can achieve the same effects as the centrifugal fans 1, 1a, and 1b according to Embodiments 1 to 3. In other words, the indoor unit 110 according to Embodiment 4 can achieve high efficiency.

[0049] Fifth Embodiment An air conditioning apparatus 100 according to a fifth embodiment will now be described in detail with reference to the drawings.

[0050] <Configuration and Operation of Air Conditioning Apparatus> Fig. 14 is a diagram showing a schematic configuration of an air conditioning apparatus 100 according to Embodiment 5. The air conditioning apparatus 100 according to Embodiment 5 is configured by the indoor unit 110 according to Embodiment 4, an outdoor unit 200, and refrigerant piping 300.

[0051] 15 and 16 are refrigerant circuit diagrams showing the flow of refrigerant in the air conditioner 100 according to Embodiment 5. Fig. 15 shows the flow during cooling operation, and Fig. 16 shows the flow during heating operation.

[0052] The outdoor unit 200 is composed of an outdoor heat exchanger 210 , an outdoor blower 220 , a compressor 230 , a four-way valve 240 , and an expansion valve 250 .

[0053] The outdoor heat exchanger 210 functions as a condenser during cooling operation and as an evaporator during heating operation. The indoor heat exchanger 130 functions as an evaporator during cooling operation and as a condenser during heating operation. The cooling operation and heating operation are switched by switching the flow path using the four-way valve 240.

[0054] The compressor 230 includes a compressor motor (not shown), a compression mechanism (not shown) driven by the compressor motor, and a sealed container (not shown) that covers the compressor motor and the compression mechanism. The compressor 230 compresses the refrigerant it draws in and discharges it.

[0055] The four-way valve 240 changes the flow direction of the refrigerant flowing through the refrigerant circuit. The expansion valve 250 reduces the pressure of the refrigerant to expand it.

[0056] The operation of the condenser will now be described. The air conditioning apparatus 100 flows high-temperature, high-pressure refrigerant gas delivered from the compressor 230 into the condenser, where it exchanges heat with a medium (e.g., air) to condense the refrigerant gas and deliver it as low-temperature, high-pressure liquid refrigerant. Heat exchange with the medium occurs when the refrigerant flows into the condenser and passes between two fins (not shown) in a direction perpendicular to the axial direction of the heat transfer tube. This allows heat to be released outside the condenser in an amount equal to the amount of heat in the refrigerant reduced by condensation.

[0057] During cooling operation, heat is radiated from the outdoor heat exchanger 210, which functions as a condenser, and warm air is expelled to the outside of the outdoor unit 200 by the outdoor blower 220. During heating operation, heat is radiated from the indoor heat exchanger 130, which functions as a condenser, and warm air is supplied indoors by the centrifugal blowers 1, 1a, and 1b.

[0058] The operation of the evaporator will now be described. The low-temperature gas-liquid mixed refrigerant delivered from the expansion valve 250 flows into the evaporator, where it exchanges heat with a medium (e.g., air), evaporating the gas-liquid mixed refrigerant and delivering it as low-temperature refrigerant gas. Heat exchange with the medium occurs when the refrigerant flows into the evaporator and passes between two fins in a direction perpendicular to the axial direction of the heat transfer tube. This cools the outside of the evaporator by the amount of heat added by the refrigerant due to evaporation.

[0059] During heating operation, the air is cooled by the outdoor heat exchanger 210, which functions as an evaporator, and the outdoor blower 220 blows cool air outside the outdoor unit 200. During cooling operation, the air is cooled by the indoor heat exchanger 130, which functions as an evaporator, and the centrifugal blowers 1, 1a, and 1b supply cool air into the room.

[0060] The refrigerant is a mixed refrigerant containing an ethylenic fluorohydrocarbon having a carbon-carbon double bond. By using a mixed refrigerant containing an ethylenic fluorohydrocarbon having a carbon-carbon double bond, the operating pressure of the compressor 230 is reduced, and a disproportionation reaction of the refrigerant can be prevented. In the fifth embodiment, the refrigerant is a mixed refrigerant containing R1123. Note that the refrigerant is not limited to R1123, and may be a mixed refrigerant containing another ethylenic fluorohydrocarbon.

[0061] The refrigerant may contain one or more ethylene-based fluorocarbons, and may be a mixed refrigerant made by mixing an ethylene-based fluorocarbon with another refrigerant. For example, the refrigerant may be a mixed refrigerant made by mixing R1123 and R32. The proportion of R1123 in this mixed refrigerant is preferably set within a range of 40 wt% to 60 wt%. By setting the proportion of R1123 within a range of 40 wt% to 60 wt%, a refrigerant with low global warming potential (GWP) and high refrigerant performance can be constructed. Note that R1123 is not limited to R32, and may be mixed with one or more of R1234yf, R1234ze(E), R1234ze(Z), R125, and R134a.

[0062] The refrigerant may also be a refrigerant containing two or more types of ethylenic fluorocarbons. For example, R1123 may be mixed with one or more of the ethylenic fluorocarbons R1141, R1132a, R1132(E), and R1132(Z). Furthermore, the refrigerant may be a mixed refrigerant of R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, and R459A.

[0063] The refrigerant may also be any one of R1234yf, R1234ze, R32, and R290.

[0064] <Effects of the Air Conditioning Apparatus> The air conditioning apparatus 100 according to Embodiment 5 includes the indoor unit 110 according to Embodiment 4, and therefore can achieve the same effects as the indoor unit 110 according to Embodiment 4. In other words, the air conditioning apparatus 100 according to Embodiment 5 can achieve high efficiency.

[0065] The centrifugal fans 1, 1a, and 1b described in the first to third embodiments can be mounted on ventilation fans, electric vacuum cleaners, hand dryers, and the like.

[0066] The features of the above-described embodiments can be combined with each other.

[0067] REFERENCE SIGNS LIST 1 Centrifugal blower, 1a Centrifugal blower, 1b Centrifugal blower, 2 Impeller, 2a Impeller, 2b Impeller, 3 Casing, 4 Intake port, 5 Outlet port, 10 Main plate, 12 Outermost peripheral end portion, 20 Air flow guiding portion, 21 First inclined portion, 22 Second inclined portion, 23 Connection portion, 24 Slit, 40 Side plate, 60 Blade, 61 Outlet port, 120 Indoor unit housing, 123 Indoor unit intake port, 124 Indoor unit outlet port, 200 Outdoor unit.

Claims

1. An impeller comprising: a main plate that is driven to rotate about an axis; an annular side plate that is arranged axially opposite the main plate; a plurality of blades that are arranged between the main plate and the side plate; and an airflow guide portion that is provided on the main plate and has a first inclined portion that is formed so that the axial distance between the main plate and the side plate becomes wider toward the inner diameter side of the main plate, wherein the airflow guide portion is provided on the inner diameter side of the outermost peripheral end of the main plate.

2. The impeller according to claim 1, wherein an outlet for blowing out air in a direction perpendicular to the axial direction is formed between the plurality of blades, and the airflow guide portion is provided on the inner diameter side of the outlet.

3. The impeller according to claim 1 or 2, wherein the first inclined portion is a flat surface.

4. An impeller as claimed in any one of claims 1 to 3, wherein the airflow guide section has a second inclined section formed so that the axial distance between the main plate and the side plate widens from the first inclined section towards the outer diameter side of the main plate, and a connecting section is provided that connects the first inclined section and the second inclined section.

5. The impeller according to claim 4, wherein the connecting portion has a circular chamfered portion.

6. The impeller according to claim 5, wherein the chamfered portion is circular with a radius of 1 mm or more.

7. The impeller according to any one of claims 1 to 6, wherein the angle formed between the main plate and the first inclined portion is θ1 [degrees], and 0 < θ1 ≦ 45 holds true.

8. The impeller according to any one of claims 1 to 7, wherein the relationship 0 < L2 / L1 ≦ 0.5 holds, where L1 is the distance in the axial direction between the main plate and the side plate, and L2 is the maximum length of the airflow guiding portion in the axial direction from the main plate.

9. An impeller according to any one of claims 1 to 8, wherein L2 is the maximum length of the airflow guiding portion in the axial direction from the main plate, and L3 is the shortest distance from the outermost edge of the main plate to the airflow guiding portion, such that L2 ≥ L3 holds.

10. An impeller according to any one of claims 1 to 9, wherein the airflow guide portion has a slit.

11. The impeller according to claim 10, wherein at least two or more slits are provided.

12. A centrifugal blower comprising: an impeller according to any one of claims 1 to 11; a motor connected to the main plate; and a casing in which an intake port and an outlet port are formed.

13. An indoor unit comprising: the centrifugal blower according to claim 12; and an indoor unit housing in which an indoor unit inlet and an indoor unit outlet are formed.

14. An air conditioning apparatus comprising: an indoor unit according to claim 13; and an outdoor unit connected to the indoor unit.

15. A ventilation fan comprising: the centrifugal blower according to claim 12; and a ventilation fan housing in which a ventilation fan inlet and a ventilation fan outlet are formed.

16. A vacuum cleaner comprising: the centrifugal blower according to claim 12; and a vacuum cleaner housing in which a vacuum cleaner suction port and a vacuum cleaner outlet are formed.

17. A hand dryer comprising: the centrifugal blower according to claim 12; and a hand dryer housing in which a hand dryer inlet and a hand dryer outlet are formed.

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