Impeller, centrifugal blower, and indoor unit
Patent Information
- Authority / Receiving Office
- GB · GB
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2022-01-17
- Publication Date
- 2026-06-15
Smart Images
Figure 00000001_0000 
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Abstract
Description
Impellers, centrifugal fans, and indoor units
[0001] The present disclosure relates to an impeller, a centrifugal blower, and an indoor unit.
[0002] Impellers for centrifugal fans are known. For example, Patent Document 1 describes an impeller including a side plate having a fitting recess formed therein into which an end of a hollow blade is fitted.
[0003] Japanese Patent Application Laid-Open No. 2005-155510
[0004] In the impeller described above, in order to securely contact the end of the hollow blade with the inner surface of the fitting recess to fix the hollow blade to the side plate, a gap is provided between the side plate and the portion of the hollow blade other than the portion that contacts the inner surface of the fitting recess. Air flows from the positive pressure side of the hollow blade to the negative pressure side of the hollow blade through this gap, which has been a problem in that it reduces the air blowing efficiency of the impeller.
[0005] In view of the above circumstances, one of the objects of the present disclosure is to provide an impeller having a structure that can suppress a decrease in air blowing efficiency, a centrifugal blower equipped with such an impeller, and an indoor unit equipped with such a centrifugal blower.
[0006] One aspect of the impeller according to the present disclosure is an impeller rotatable around a rotation axis, the impeller comprising: a base; a shroud portion located on a first side of the base in an axial direction of the rotation axis; and a plurality of blade portions located axially between the base and the shroud portion and arranged at intervals in a rotation direction of the impeller, the shroud portion having a shroud main body and a plurality of protruding accommodating portions that protrude from the shroud main body to the first side and open to a second side opposite to the first side in the axial direction, each of the plurality of blade portions having a blade main body and a protruding portion that protrudes from the blade main body to the first side, and one end of the blade main body in an extension direction of the blade main body as viewed in the axial direction is protruded from the protruding portion to the first side. the protruding portions of the plurality of blade portions are accommodated in the plurality of protruding accommodating portions, each of the plurality of protruding accommodating portions having a first accommodating portion and a second accommodating portion connected to an end of the first accommodating portion in the extension direction, the protruding portion having a first convex portion accommodated in the first accommodating portion and fixed to the shroud portion, and a second convex portion connected to an end of the first convex portion in the extension direction and accommodated in the second accommodating portion, the first convex portion being fixed in contact with a surface of an inner surface of the first accommodating portion located on the first side, and the second convex portion facing a surface of an inner surface of the second accommodating portion located on the first side across a gap.
[0007] One aspect of a centrifugal fan according to the present disclosure includes the above-described impeller and a drive unit that rotates the impeller about the rotation axis.
[0008] One aspect of an indoor unit according to the present disclosure is an indoor unit for an air conditioner, comprising the centrifugal blower described above and a heat exchanger to which air is sent by the centrifugal blower.
[0009] According to the present disclosure, in a centrifugal blower, it is possible to suppress a decrease in the blowing efficiency of the impeller.
[0010] 17 is a schematic diagram showing a general configuration of an air conditioner according to Embodiment 1. FIG. 17 is a perspective view showing an indoor unit according to Embodiment 1. FIG. 17 is a cross-sectional view showing an indoor unit according to Embodiment 1. FIG. 17 is a perspective view showing an impeller according to Embodiment 1. FIG. 17 is a bottom view of the impeller according to Embodiment 1. FIG. 17 is a cross-sectional view showing a protruding accommodating portion and a protruding portion according to Embodiment 1, taken along VI-VI in FIG. 5. FIG. 17 is a perspective view showing a protruding accommodating portion according to Embodiment 1. FIG. 17 is a cross-sectional view showing a blade portion according to Embodiment 1. FIG. 17 is a cross-sectional view showing a part of the impeller according to Embodiment 1, taken along IX-IX in FIG. 5. FIG. 17 is a cross-sectional view showing a part of the impeller according to Embodiment 1, taken along X-X in FIG. 5. FIG. 17 is a perspective view showing a part of the impeller according to Embodiment 2. FIG. 17 is a bottom view of a part of the impeller according to Embodiment 2. FIG. 17 is a cross-sectional view showing a part of the impeller according to Embodiment 3. FIG. 17 is a cross-sectional view showing a part of the impeller according to Embodiment 3. FIG. 17 is a perspective view showing a part of the blade portion according to Embodiment 3. FIG. 17 is a perspective view showing a part of the impeller according to Embodiment 4. FIG. 17 is a cross-sectional view showing a part of an impeller according to a comparative example. FIG. 17 is a cross-sectional view showing a part of an impeller according to a comparative example, taken along XVIII-XVIII in FIG.
[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure. In addition, in the following drawings, the scale and number of each structure may differ from the scale and number of the actual structure in order to make each configuration easier to understand.
[0012] The drawings also show the Z axis where appropriate. The Z axis indicates the vertical direction. The side of the vertical direction Z toward which the arrow of the Z axis points (+Z side) is the upper side, and the side of the vertical direction Z opposite to the side toward which the arrow of the Z axis points (-Z side) is the lower side. Note that in the following embodiments, the vertical direction Z corresponds to the axial direction of the rotation axis R, which will be described later. The lower side corresponds to the "first side" of the axial direction of the rotation axis R, and the upper side corresponds to the "second side" opposite to the first side of the axial direction of the rotation axis R.
[0013] Embodiment 1. Fig. 1 is a schematic diagram showing the general configuration of an air conditioner 100 in Embodiment 1. As shown in Fig. 1, the air conditioner 100 includes an indoor unit 10, an outdoor unit 20, and a circulation path section 30. The indoor unit 10 is disposed indoors. The outdoor unit 20 is disposed outdoors. The indoor unit 10 and the outdoor unit 20 are connected to each other by the circulation path section 30 through which a refrigerant 33 circulates. The indoor unit 10 and the outdoor unit 20 are heat exchange units that exchange heat with the air.
[0014] The air conditioner 100 is able to adjust the temperature of the air in the room by exchanging heat between the refrigerant 33 flowing in the circulation path section 30 and the air in the room where the indoor unit 10 is located. Examples of the refrigerant 33 include fluorine-based refrigerants or hydrocarbon-based refrigerants with low global warming potential (GWP).
[0015] The outdoor unit 20 has a compressor 21, a heat exchanger 23, a flow rate adjustment valve 24, a blower 25, and a four-way valve 22. The compressor 21, the heat exchanger 23, the flow rate adjustment valve 24, and the four-way valve 22 are connected by a circulation path portion 30.
[0016] The four-way valve 22 is provided in a portion of the circulation path section 30 that is connected to the discharge side of the compressor 21. The four-way valve 22 can reverse the direction of the refrigerant 33 flowing through the circulation path section 30 by switching a portion of the path of the circulation path section 30. When the path connected by the four-way valve 22 is the path shown by the solid line on the four-way valve 22 in Fig. 1, the refrigerant 33 flows through the circulation path section 30 in the direction shown by the solid arrow in Fig. 1. On the other hand, when the path connected by the four-way valve 22 is the path shown by the dashed line on the four-way valve 22 in Fig. 1, the refrigerant 33 flows through the circulation path section 30 in the direction shown by the dashed arrow in Fig. 1.
[0017] The indoor unit 10 includes a housing 11, a heat exchanger 14, and a centrifugal fan 40. The indoor unit 10 is capable of cooling operation to cool the air in the room in which the indoor unit 10 is located, and heating operation to warm the air in the room in which the indoor unit 10 is located.
[0018] When the indoor unit 10 is in cooling operation, the refrigerant 33 flowing in the circulation path portion 30 flows in the direction shown by the solid arrow in Fig. 1. In other words, when the indoor unit 10 is in cooling operation, the refrigerant 33 flowing in the circulation path portion 30 circulates through the compressor 21, the heat exchanger 23 of the outdoor unit 20, the flow control valve 24, and the heat exchanger 14 of the indoor unit 10 in that order, before returning to the compressor 21. During cooling operation, the heat exchanger 23 in the outdoor unit 20 functions as a condenser, and the heat exchanger 14 in the indoor unit 10 functions as an evaporator.
[0019] On the other hand, when the indoor unit 10 is in heating operation, the refrigerant 33 flowing in the circulation path portion 30 flows in the direction shown by the dashed line in Fig. 1. In other words, when the indoor unit 10 is in heating operation, the refrigerant 33 flowing in the circulation path portion 30 circulates through the compressor 21, the heat exchanger 14 of the indoor unit 10, the flow control valve 24, and the heat exchanger 23 of the outdoor unit 20 in that order, before returning to the compressor 21. In heating operation, the heat exchanger 23 in the outdoor unit 20 functions as an evaporator, and the heat exchanger 14 in the indoor unit 10 functions as a condenser.
[0020] Next, the indoor unit 10 of the first embodiment will be described in further detail. FIG. 2 is a perspective view showing the indoor unit 10. FIG. 3 is a cross-sectional view showing the indoor unit 10. As shown in FIGS. 2 and 3, the indoor unit 10 in the first embodiment is a ceiling-mounted indoor unit that is installed by being embedded in a ceiling. As shown in FIG. 3, the housing 11 houses a heat exchanger 14 and a centrifugal blower 40 therein. The housing 11 has a housing main body 12 that houses the heat exchanger 14 and the centrifugal blower 40 therein, and a decorative panel 13 attached below the housing main body 12. The housing main body 12 is installed by being embedded in the ceiling of the room in which the indoor unit 10 is installed. The decorative panel 13 is exposed to the room in which the indoor unit 10 is installed.
[0021] The heat exchanger 14 is housed inside the housing main body 12. Air is sent to the heat exchanger 14 by a centrifugal fan 40. The heat exchanger 14 is in the shape of a frame that surrounds the centrifugal fan 40. The heat exchanger 14 is disposed opposite an exhaust port 60b, which will be described later.
[0022] The indoor unit 10 has an air inlet 10a and an air outlet 10b. The air inlet 10a and the air outlet 10b open on the underside of the decorative panel 13. As shown in Fig. 2, the air inlet 10a is located in the center of the indoor unit 10 when viewed in the vertical direction Z. Multiple air outlets 10b are provided. The multiple air outlets 10b are arranged surrounding the air inlet 10a when viewed in the vertical direction Z. Four air outlets 10b are provided.
[0023] The centrifugal blower 40 is a blower that sends air to the heat exchanger 14. When the centrifugal blower 40 is driven, air flows inside the indoor unit 10. In Fig. 3, the arrow AF indicates the air flow caused by driving the centrifugal blower 40. As shown by the arrow AF in Fig. 3, when the centrifugal blower 40 is driven, air is sucked into the indoor unit 10 through the air inlet 10a. The indoor air sucked into the indoor unit 10 through the air inlet 10a passes through the heat exchanger 14 and is blown out into the room through the four air outlets 10b.
[0024] The centrifugal blower 40 is fixed to the underside of the top plate 12a of the housing main body 12. The centrifugal blower 40 includes a drive unit 50 and an impeller 60. The drive unit 50 rotates the impeller 60 around a rotation axis R. The rotation axis R, which is shown appropriately in the drawings, is an imaginary axis extending in the vertical direction Z. In other words, the axial direction of the rotation axis R is the vertical direction Z. When viewed in the vertical direction Z, the rotation axis R passes through the center of the indoor unit 10.
[0025] In the following description, unless otherwise specified, the radial direction about the rotation axis R will be simply referred to as the "radial direction," and the circumferential direction around the rotation axis R will be referred to as the "rotational direction." The rotational direction is indicated by an arrow θ in the figures where appropriate. The impeller 60 rotates in the direction indicated by the arrow θ. The side of the rotational direction toward which the arrow θ points (+θ side) is the "forward side," and the side of the rotational direction opposite to the side toward which the arrow θ points (-θ side) is the "rearward side." The forward side of the rotational direction (+θ side) is the side that moves counterclockwise around the rotation axis R when viewed from below. The rearward side of the rotational direction (-θ side) is the side that moves clockwise around the rotation axis R when viewed from below.
[0026] In the first embodiment, the drive unit 50 is a motor. The drive unit 50 has a drive unit main body 51 fixed to the underside of the top plate 12a, and a rotating shaft 52 that protrudes downward from inside the drive unit main body 51. The rotating shaft 52 is part of the rotor in the drive unit 50. The rotating shaft 52 is rotatable around the rotation axis R. Note that the drive unit 50 may have any configuration as long as it can rotate the impeller 60 around the rotation axis R.
[0027] The impeller 60 is rotatable around the rotation axis R. The impeller 60 is made of, for example, resin. The impeller 60 is fixed to a portion of the rotary shaft 52 of the drive unit 50 that protrudes downward beyond the drive unit main body 51 via a connecting member 53. The connecting member 53 is a cylindrical member centered on the rotation axis R. The connecting member 53 is fixed to the outer circumferential surface of the rotary shaft 52. FIG. 4 is a perspective view showing the impeller 60. FIG. 5 is a view of the impeller 60 as viewed from below. As shown in FIGS. 3 to 5 , the impeller 60 includes a base 61, a shroud 62, and a plurality of blades 63.
[0028] The base 61 is fixed to the rotary shaft 52 via a connecting member 53. As shown in FIG. 4, the base 61 has an annular plate portion 61a, a bulging portion 61b, and a plurality of guide portions 61f. The annular plate portion 61a is annular and has a shape centered on the rotation axis R. The bulging portion 61b protrudes downward from the radial inner edge of the annular plate portion 61a. The bulging portion 61b is cylindrical and has a center on the rotation axis R. As shown in FIG. 3, the drive unit main body 51 is located inside the bulging portion 61b. The bulging portion 61b has a peripheral wall portion 61c, a bottom plate portion 61d, and a cylindrical portion 61e.
[0029] The peripheral wall portion 61c is cylindrical and opens upward, with its center on the rotation axis R. The inner diameter and outer diameter of the peripheral wall portion 61c decrease downward. The bottom plate portion 61d is connected to the lower end of the peripheral wall portion 61c. The bottom plate portion 61d is annular and has its center on the rotation axis R. The tubular portion 61e protrudes downward from the radial inner edge of the bottom plate portion 61d. The tubular portion 61e is cylindrical and opens downward, with its center on the rotation axis R. A connecting member 53 is fixed to the inner peripheral surface of the tubular portion 61e. The tubular portion 61e is fixed to the rotation shaft 52 via the connecting member 53.
[0030] As shown in FIG. 4 , the guide portions 61f are formed on the underside of the annular plate portion 61a. When viewed in the vertical direction Z, the guide portions 61f extend in a direction inclined obliquely in the rotational direction relative to the radial direction and have an elongated, generally U-shaped shape that opens radially outward. The guide portions 61f are positioned closer to the front side (+θ side) in the rotational direction as they extend radially inward. The guide portions 61f are arranged at intervals around the circumference in the rotational direction. In the first embodiment, seven guide portions 61f are provided. The intervals between the guide portions 61f may be equal or may be different from each other.
[0031] The shroud portion 62 is located below and spaced apart from the annular plate portion 61a of the base portion 61. In other words, the shroud portion 62 is located on the lower side (first side) of the base portion 61 in the axial direction of the rotation axis R. The shroud portion 62 has an annular shape centered on the rotation axis R. The radially inner edge of the shroud portion 62 is located radially outward from the bulging portion 61b. The shroud portion 62 is cylindrical, centered on the rotation axis R, and open on both sides in the vertical direction Z. The inner diameter and outer diameter of the shroud portion 62 decrease downward. The shroud portion 62 has a shroud main body portion 62a and a plurality of protruding accommodating portions 64.
[0032] The shroud main body 62a has a cylindrical shape centered on the rotation axis R and open on both sides in the vertical direction Z. The inner diameter and the outer diameter of the shroud main body 62a decrease toward the bottom. As shown in Figure 3, in a cross section perpendicular to the rotation direction, the shape of the shroud main body 62a is an arc that is convex radially inward and obliquely upward.
[0033] The radially inner edge of the shroud body 62a is the lower end of the shroud body 62a. The radially inner edge of the shroud body 62a is the air intake 60a that opens downward. The air intake 60a is located above and spaced apart from the air inlet 10a of the indoor unit 10.
[0034] The radially outer edge of the shroud main body 62a is the upper end of the shroud main body 62a. As shown in FIG. 4 , the space between the radially outer edge of the shroud main body 62a and the radially outer edge of the annular plate 61a in the vertical direction Z is partitioned in the rotational direction by a plurality of blades 63, thereby forming a plurality of exhaust ports 60b that open radially outward. The plurality of exhaust ports 60b are arranged at intervals around one circumference in the rotational direction. In the first embodiment, seven exhaust ports 60b are provided. As shown in FIG. 3 , a heat exchanger 14 is arranged radially outward of each exhaust port 60b so as to face each other. The intervals between the plurality of exhaust ports 60b may be equal or may be different from each other.
[0035] When the impeller 60 is rotated around the rotation axis R by the drive unit 50, air drawn into the indoor unit 10 through the air inlet 10a flows into the impeller 60 through the air inlet 60a. The air that has flowed into the impeller 60 is discharged radially outward from the multiple air outlets 60b. The air discharged from the multiple air outlets 60b passes through the heat exchanger 14 and is blown out into the room through the multiple air outlets 10b.
[0036] FIG. 6 is a cross-sectional view showing the protruding accommodating portion 64 and a protruding portion 66 (described later), taken along the line VI-VI in FIG. 5 . FIG. 7 is a perspective view showing the protruding accommodating portion 64. As shown in FIGS. 6 and 7 , the multiple protruding accommodating portions 64 protrude downward from the shroud main body portion 62a. As shown in FIG. 6 , the multiple protruding accommodating portions 64 are hollow. The multiple protruding accommodating portions 64 are open upward. As shown in FIG. 5 , each of the multiple protruding accommodating portions 64 extends obliquely toward the rotational direction relative to the radial direction, as viewed in the vertical direction Z. The radially inner end of each protruding accommodating portion 64 is located forward (+θ side) in the rotational direction relative to the radially outer end of each protruding accommodating portion 64. As viewed in the vertical direction Z, each protruding accommodating portion 64 extends obliquely in a linear manner so as to be positioned forward in the rotational direction as it extends radially inward.
[0037] The direction in which each protruding housing portion 64 extends as viewed in the vertical direction Z is the extension direction in which a blade main body portion 65 (described later) extends as viewed in the vertical direction Z. In the following description, the extension direction of the blade main body portion 65 (described later) as viewed in the vertical direction Z is referred to as the "extension direction." The radially inner side in the extension direction is referred to as the inner extension direction, and the radially outer side in the extension direction is referred to as the outer extension direction. The inner extension direction is the side that is radially inner and forward in the direction of rotation (+θ side). The outer extension direction is the side that is radially outer and rearward in the direction of rotation (−θ side). For example, the left side in FIG. 6 is the inner extension direction, and the right side in FIG. 6 is the outer extension direction.
[0038] As shown in Figures 6 and 7, each of the multiple protruding accommodating portions 64 has a first accommodating portion 64a. The first accommodating portion 64a has a generally rectangular box shape extending in the direction in which the protruding accommodating portion 64 extends. The first accommodating portion 64a has an outer portion 64c and an inner portion 64d. The outer portion 64c is the portion of the first accommodating portion 64a that is on the outer side in the extension direction. The inner portion 64d is the portion of the first accommodating portion 64a that is on the inner side in the extension direction. The outer end of the outer portion 64c in the extension direction is the outer end of the first accommodating portion 64a in the extension direction. The inner end of the inner portion 64d in the extension direction is the inner end of the first accommodating portion 64a in the extension direction. The outer portion 64c is located radially outward of the inner portion 64d. The inner portion 64d is connected to the inner end of the outer portion 64c in the extension direction.
[0039] The lower end of the outer portion 64c is located higher than the lower end of the inner portion 64d. The outer portion 64c is located at a position recessed upward relative to the inner portion 64d. By recessing the outer portion 64c upward in this manner, it is possible to prevent the protruding accommodating portion 64 from interfering with other components located below the radially outer portion of the shroud portion 62. As shown in FIG. 6 , a side wall portion 64e on the outer side in the extension direction of the outer portion 64c extends from the shroud main body portion 62a in the vertical direction Z. A stepped wall portion 64g between the outer portion 64c and the inner portion 64d is inclined relative to the vertical direction Z in the extension direction of the protruding accommodating portion 64. The stepped wall portion 64g is located more inward in the extension direction as it extends downward.
[0040] Each of the multiple protruding accommodating portions 64 has an inner accommodating portion 64b. The inner accommodating portion 64b is a second accommodating portion connected to the end of the first accommodating portion 64a in the extension direction. The inner accommodating portion 64b is connected to the end of the first accommodating portion 64a on the inner side in the extension direction. More specifically, the inner accommodating portion 64b is connected to the inner end of the inner portion 64d in the extension direction. As described above, in the first embodiment, each of the multiple protruding accommodating portions 64 has, as a second accommodating portion, the inner accommodating portion 64b connected to the end located radially inner of both ends of the first accommodating portion 64a in the extension direction. The inner end of the inner accommodating portion 64b in the extension direction is the inner end of the protruding accommodating portion 64. The inner accommodating portion 64b is box-shaped and open upward. The interior of the inner accommodating portion 64b is connected to the interior of the first accommodating portion 64a.
[0041] The lower end of the inner accommodating portion 64b is located above the lowest portion of the first accommodating portion 64a. In the first embodiment, the lowest portion of the first accommodating portion 64a is the lower end of the inner portion 64d. The lower end of the inner accommodating portion 64b is recessed higher than the lower end of the inner end of the inner portion 64d in the extension direction. A step wall portion 64h between the inner accommodating portion 64b and the first accommodating portion 64a extends in the vertical direction Z.
[0042] 5 and 7, the inner storage portion 64b has a generally triangular shape when viewed in the vertical direction Z. As shown in Fig. 6, a side wall portion 64f on the inner side of the extension direction of the inner storage portion 64b is inclined in the extension direction with respect to the vertical direction Z. The side wall portion 64f is positioned more outward in the extension direction as it extends downward. The side wall portion 64f extends along an inner protrusion 66b, which will be described later.
[0043] As shown in FIG. 4 , the plurality of blade portions 63 are located between the base portion 61 and the shroud portion 62 in the vertical direction Z. More specifically, the plurality of blade portions 63 are located between the annular plate portion 61 a and the shroud portion 62 in the vertical direction Z. The plurality of blade portions 63 connect the base portion 61 and the shroud portion 62. The plurality of blade portions 63 are arranged at intervals in the rotation direction of the impeller 60. The plurality of blade portions 63 are arranged at intervals from one another around one circumference in the rotation direction. In the first embodiment, seven blade portions 63 are provided. The intervals between the plurality of blade portions 63 may be equal or may be different from one another.
[0044] FIG. 8 is a perspective view showing the blade portion 63. As shown in FIG. 8, the blade portion 63 is configured by combining a first blade member 63a and a second blade member 63b in a direction perpendicular to both the extension direction and the vertical direction Z. The first blade member 63a is a flat, box-shaped member that opens radially outward. The second blade member 63b is a plate-shaped member that closes the radially outward opening of the first blade member 63a. The first blade member 63a and the second blade member 63b are fixed to each other, for example, by ultrasonic welding. FIG. 9 is a cross-sectional view showing a portion of the impeller 60, taken along line IX-IX in FIG. 5. As shown in FIG. 9, a gap is provided between the first blade member 63a and the second blade member 63b. In the first embodiment, the multiple blade portions 63 are hollow blade portions. Note that in FIG. 9, arrows AF indicate the flow of air when the impeller 60 rotates.
[0045] The first blade member 63a constitutes the surface of the blade portion 63 that faces radially inward. In the first embodiment, the surface of the blade portion 63 that faces radially inward is the negative pressure surface 63m. As shown in FIG. 4, the negative pressure surface 63m faces radially inward and toward the rear side (-θ side) in the direction of rotation. The second blade member 63b is located radially outward of the first blade member 63a. The second blade member 63b constitutes a part of the surface of the blade portion 63 that faces radially outward. In the first embodiment, the surface of the blade portion 63 that faces radially outward is the positive pressure surface 63p. The positive pressure surface 63p faces radially outward and toward the front side (+θ side) in the direction of rotation.
[0046] Each of the multiple blade portions 63 has a blade main body portion 65. When viewed in the vertical direction Z, the blade main body portion 65 extends obliquely in a direction inclined toward the rotational direction relative to the radial direction. When viewed in the vertical direction Z, the blade main body portion 65 is positioned toward the forward side (+θ side) in the rotational direction as it moves radially inward. As described above, the direction in which the blade main body portion 65 extends when viewed in the vertical direction Z is the extension direction.
[0047] One end of the blade main body 65 in the extension direction is located radially inward about the rotation axis R and forward in the direction of rotation (+θ side) than the other end of the blade main body 65 in the extension direction. In the first embodiment, the one end of the blade main body 65 in the extension direction is an end on the radially inner side of the blade main body 65 and an end on the forward side (+θ side) in the direction of rotation of the blade main body 65. In the first embodiment, the other end of the blade main body 65 in the extension direction is an end on the radially outer side of the blade main body 65 and an end on the backward side (−θ side) in the direction of rotation of the blade main body 65.
[0048] The blade main body 65 is located between the annular plate 61a of the base 61 and the shroud main body 62a in the vertical direction Z. As shown in FIG. 9 , the upper end of the blade main body 65 contacts the lower surface of the annular plate 61a and is fixed to the lower surface of the annular plate 61a. The upper end of the blade main body 65 is fixed to the lower surface of the annular plate 61a by, for example, laser welding. The upper end of the blade main body 65 is located inside the guide portion 61f. The side surface at the upper end of the blade main body 65 is located away from the inner surface of the guide portion 61f. The upper end of the blade main body 65 does not contact the guide portion 61f.
[0049] As shown in Fig. 8, each of the multiple blade portions 63 has a protrusion 66 that protrudes downward from the blade main body portion 65. The protrusion 66 extends in the extension direction. More specifically, the protrusion 66 extends in the same direction as the extension of the lower end portion 65a of the blade main body portion 65 when viewed in the vertical direction Z. The extension direction of the protrusion 66 is the same as the extension direction of the protrusion housing portion 64. As shown in Fig. 6, the protrusions 66 of the multiple blade portions 63 are housed in the multiple protrusion housing portions 64, respectively.
[0050] The protrusion 66 has a first protrusion 66a. The first protrusion 66a is accommodated in the first housing 64a. The first protrusion 66a has a generally rectangular parallelepiped shape extending in the extension direction. The first protrusion 66a is hollow. The first protrusion 66a is fixed in contact with a lower surface of the inner surface of the first housing 64a. This fixes the first protrusion 66a to the shroud 62. The lower surface of the inner surface of the first housing 64a faces upward. The lower surface of the first protrusion 66a is fixed to the lower surface of the inner surface of the first housing 64a by, for example, laser welding. In the first embodiment, the portion of the first protrusion 66a fixed to the first housing 64a is part of the first blade member 63a. The portion of the first protrusion 66a that is fixed to the first housing portion 64a may be part of the second blade member 63b.
[0051] The first protrusion 66a has an outer portion 66c accommodated in the outer portion 64c of the first accommodation portion 64a and an inner portion 66d accommodated in the inner portion 64d of the first accommodation portion 64a. The outer portion 66c is the outer portion of the first protrusion 66a in the extension direction. The inner portion 66d is the inner portion of the first protrusion 66a in the extension direction. The inner portion 66d is connected to the inner end of the outer portion 66c in the extension direction. The outer end of the outer portion 66c in the extension direction is the outer end of the first protrusion 66a in the extension direction. The inner end of the inner portion 66d in the extension direction is the inner end of the first protrusion 66a in the extension direction. As shown in FIG. 8 , the outer end of the outer portion 66c in the extension direction is located further inward in the extension direction than the outer end of the lower end 65a of the blade main body 65 in the extension direction.
[0052] 6, the lower end of the outer portion 66c is fixed in contact with a lower surface of the inner surface of the outer portion 64c in the first housing portion 64a. The lower end of the outer portion 66c is located higher than the lower end of the inner portion 66d. The lower end of the inner portion 66d is fixed in contact with a lower surface of the inner surface of the inner portion 64d in the first housing portion 64a.
[0053] The side wall portion 66e on the outer side in the extension direction of the outer portion 66c extends downward in the vertical direction Z from the lower end portion 65a of the blade main body portion 65. The side wall portion 66e is disposed on the inner side in the extension direction of the side wall portion 64e of the protrusion accommodating portion 64. The side wall portion 66e faces the side wall portion 64e with a gap therebetween. The side wall portion 66e does not contact the side wall portion 64e.
[0054] A step wall portion 66g between the outer portion 66c and the inner portion 66d extends in the vertical direction Z. The step wall portion 66g is disposed on the inner side of the step wall portion 64g of the protrusion accommodating portion 64 in the extension direction. The step wall portion 66g faces the step wall portion 64g across a gap. The step wall portion 66g does not contact the step wall portion 64g.
[0055] A side wall portion 66h on the inner side in the extension direction of the inner portion 66d extends downward in the vertical direction Z from the lower end portion 65a of the blade main body portion 65. The lower end portion of the side wall portion 66h is disposed on the outer side in the extension direction of the stepped wall portion 64h of the protrusion accommodating portion 64. The side wall portion 66h faces the stepped wall portion 64h with a gap therebetween. The side wall portion 66h does not contact the stepped wall portion 64h.
[0056] Each of the multiple protrusions 66 has an inner protrusion 66b. The inner protrusion 66b is a second protrusion connected to the end of the first protrusion 66a in the extension direction. As shown in FIG. 8 , the inner protrusion 66b is connected to the inner end of the first protrusion 66a in the extension direction. More specifically, the inner protrusion 66b is connected to the inner end of the inner portion 66d in the extension direction, i.e., the side wall portion 66h. As described above, in the first embodiment, each of the multiple protrusions 66 has, as a second protrusion, an inner protrusion 66b connected to the end located radially inward of both ends of the first protrusion 66a in the extension direction. The inner end of the inner protrusion 66b in the extension direction is the inner end of the protrusion 66 in the extension direction.
[0057] The inner convex portion 66b protrudes downward from the outer edge of the lower surface of an inner end portion 65b of the lower end portion 65a of the blade main body 65, which is located more inward in the extension direction than the first convex portion 66a. In the first embodiment, the inner convex portion 66b and the inner end portion 65b are part of the first blade member 63a. Note that the inner convex portion 66b and the inner end portion 65b may also be part of the second blade member 63b. The inner convex portion 66b protrudes downward from the edge on the forward side (+θ side) in the rotational direction and the edge on the radially inner side of the outer edge of the lower surface of the inner end portion 65b. When viewed in the vertical direction Z, the inner convex portion 66b extends from the radially inner edge of the side wall portion 66h of the first convex portion 66a while curving inward in the extension direction and outward in the radial direction.
[0058] The lower end of the inner convex portion 66b is located above the lowest portion of the first convex portion 66a. In the first embodiment, the lowest portion of the first convex portion 66a is the lower end of the inner portion 66d. The lower end of the inner convex portion 66b is located below the lower end of the outer portion 66c.
[0059] Of the ends of the inner protrusion 66b in the extension direction, the end opposite to the side connected to the first protrusion 66a, i.e., the inner end in the extension direction, is connected without a step to the inner end in the extension direction of the blade main body 65. The inner surface in the extension direction of the inner protrusion 66b is smoothly connected to the inner surface in the extension direction of the blade main body 65. The radially inner surface of the inner protrusion 66b is smoothly connected to the negative pressure surface 63m of the blade main body 65.
[0060] As shown in FIG. 6 , the inner protrusion 66b is accommodated within the inner accommodating portion 64b. The inner protrusion 66b faces a lower surface of the inner surface of the inner accommodating portion 64b across a gap. The lower end of the inner protrusion 66b is positioned above and spaced apart from the lower surface of the inner surface of the inner accommodating portion 64b. The inner protrusion 66b is positioned outward in the extension direction of the side wall portion 64f of the inner accommodating portion 64b. The inner protrusion 66b faces the side wall portion 64f across a gap. The gap between the inner protrusion 66b and the side wall portion 64f is smaller than the gap between the lower end of the inner protrusion 66b and the lower surface of the inner surface of the inner accommodating portion 64b. The entire inner protrusion 66b is positioned away from the inner surface of the inner accommodating portion 64b. The inner protrusion 66b does not contact the inner surface of the inner accommodating portion 64b.
[0061] FIG. 10 is a cross-sectional view showing a portion of the impeller 60, taken along the line X-X in FIG. 5. In FIG. 10, arrows AF indicate the airflow when the impeller 60 rotates. As shown in FIG. 10, a gap G1 is provided between the inner end portion 65b of the impeller main body 65 and the shroud portion 62. The gap G1 connects the positive pressure side space facing the positive pressure surface 63p and the negative pressure side space facing the negative pressure surface 63m. The gap G1 includes the gap between the inner protrusion 66b and the inner surface of the inner accommodating portion 64b, the internal space of the inner accommodating portion 64b, and the gap between the inner end portion 65b and the shroud main body 62a. The gap G1 has a labyrinth shape that is complex in the vertical direction Z due to the inner protrusion 66b being inserted into the inner accommodating portion 64b.
[0062] FIG. 17 is a cross-sectional view showing a portion of the impeller 560 of the comparative example. FIG. 18 is a cross-sectional view showing a portion of the impeller 560 of the comparative example, taken along line XVIII-XVIII in FIG. 17. In FIG. 18, arrows AF indicate the flow of air when the impeller 560 rotates. As shown in FIGS. 17 and 18, the shroud portion 562 of the impeller 560 of the comparative example is similar to the shroud portion 62 of the impeller 60 of the first embodiment, except that the protruding accommodating portion 564 does not have the inner accommodating portion 64b. The blade portion 563 of the impeller 560 of the comparative example is similar to the blade portion 63 of the impeller 60 of the first embodiment, except that the protruding portion 566 does not have the inner convex portion 66b.
[0063] In the impeller 560 of the comparative example, a gap G2 is provided between the inner end portion 65b of the blade main body 65 and the inner surface of the shroud main body 62a. As shown in FIG. 18 , the gap G2 extends radially along the inner surface of the shroud main body 62a. The gap G2 opens on both radial sides and connects the pressure side space facing the pressure surface 63p with the negative pressure side space facing the negative pressure surface 63m. Therefore, in the impeller 560 of the comparative example, as shown by arrow AF in FIG. 18 , air may flow through the gap G2 from the pressure side space facing the pressure surface 63p to the negative pressure side space facing the negative pressure surface 63m. This reduces the air blowing efficiency of the impeller 560.
[0064] In contrast, according to the first embodiment, each of the multiple protruding accommodating portions 64 in the shroud portion 62 has a first accommodating portion 64a and an inner accommodating portion 64b connected to an end of the first accommodating portion 64a in the extension direction. The protruding portion 66 in the blade portion 63 has a first convex portion 66a housed in the first accommodating portion 64a and fixed to the shroud portion 62, and an inner convex portion 66b connected to an end of the first convex portion 66a in the extension direction and housed in the inner accommodating portion 64b. The first convex portion 66a is fixed in contact with a lower surface of the inner surface of the first accommodating portion 64a. The inner convex portion 66b faces a lower surface of the inner surface of the inner accommodating portion 64b across a gap. As described above, the provision of the inner accommodating portion 64b and the inner convex portion 66b accommodated within the inner accommodating portion 64b allows the gap G1 between the inner end portion 65b of the blade main body 65 and the shroud main body 62a to have a complex shape as described above. This makes it difficult for air to pass through the gap G1. This prevents air from flowing through the gap G1 from the positive pressure side space facing the positive pressure surface 63p to the negative pressure side space facing the negative pressure surface 63m. Therefore, in the centrifugal blower 40, a decrease in the blowing efficiency of the impeller 60 can be suppressed. Furthermore, because the inner convex portion 66b does not contact the lower surface of the inner surface of the inner accommodating portion 64b, the first convex portion 66a can be suitably brought into contact with the lower surface of the inner surface of the first accommodating portion 64a.
[0065] Furthermore, according to the first embodiment, each of the multiple protruding accommodating portions 64 has, as a second accommodating portion, an inner accommodating portion 64b connected to the radially inner end of one of the end portions of the first accommodating portion 64a in the extension direction. The protruding portion 66 has, as a second convex portion, an inner convex portion 66b connected to the radially inner end of one of the end portions of the first accommodating portion 66a in the extension direction. The inner convex portion 66b is accommodated within the inner accommodating portion 64b. Therefore, air flow from the positive pressure side to the negative pressure side on the inner side of the extension direction of the first accommodating portion 66a can be suppressed. The inner portion of the blade portion 63 in the extension direction pushes aside the air drawn through the intake port 60a, and therefore, air pressure tends to be high, particularly on the positive pressure side. Therefore, by suppressing air flow from the positive pressure side to the negative pressure side on the inner side of the extension direction of the first accommodating portion 66a, a decrease in the air blowing efficiency of the impeller 60 can be suppressed.
[0066] Furthermore, according to the first embodiment, the lower end of the inner accommodating portion 64b is located above the lowest portion of the first accommodating portion 64a. The lower end of the inner convex portion 66b is located above the lowest portion of the first convex portion 66a. Therefore, even if the inner accommodating portion 64b and the inner convex portion 66b are provided, the inner accommodating portion 64b does not protrude below the first accommodating portion 64a. This prevents the inner accommodating portion 64b from creating air resistance when the impeller 60 rotates. Furthermore, for example, when laser welding the first convex portion 66a and the first accommodating portion 64a, a glass plate or the like may be pressed against the first accommodating portion 64a from below to tightly contact the lower surface of the first convex portion 66a with the lower surface of the inner surface of the first accommodating portion 64a. In this case, since the inner storage portion 64b does not protrude downward from the first storage portion 64a, the glass plate or the like can be pressed against the first storage portion 64a in an appropriate manner. Therefore, the first protrusion 66a and the first storage portion 64a can be fixed to each other in an appropriate manner by laser welding.
[0067] Furthermore, according to the first embodiment, the entire inner convex portion 66b is positioned away from the inner surface of the inner accommodating portion 64b. In other words, the inner convex portion 66b does not contact the inner surface of the inner accommodating portion 64b. Therefore, when minute vibrations occur in the blade portion 63, the vibrating inner convex portion 66b can be prevented from contacting the inner surface of the inner accommodating portion 64b. This can suppress noise generated when the impeller 60 rotates. In the first embodiment, portions of the blade portion 63 other than the portions fixed by laser welding do not contact the shroud portion 62. Therefore, it is possible to more effectively prevent the vibrating portions of the blade portion 63 from contacting the shroud portion 62, and it is possible to more effectively suppress noise generated when the impeller 60 rotates.
[0068] Furthermore, according to the first embodiment, the end of the inner convex portion 66b in the extension direction, which is opposite to the end connected to the first convex portion 66a, is connected to the end of the blade main body 65 in the extension direction without any step. Therefore, no step is formed between the inner convex portion 66b and the blade main body 65, and no gap is formed between the step and the shroud main body 62a. As a result, air does not flow from the positive pressure side to the negative pressure side through the gap between the step and the shroud main body 62a. Therefore, a decrease in the air blowing efficiency of the impeller 60 can be more effectively suppressed.
[0069] Embodiment 2. Figure 11 is a perspective view showing a part of impeller 260 in embodiment 2. Figure 12 is a view of a part of impeller 260 in embodiment 2 seen from below. In the following description, the same components as those in the above-described embodiments will be denoted by the same reference numerals as appropriate, and the description may be omitted.
[0070] 11 and 12 , the shroud portion 262 of the impeller 260 has a covering portion 267 that protrudes downward from the shroud main body 62a. The covering portion 267 extends from the radially outer side of the inner accommodating portion 64b to the front side in the rotational direction (+θ side) while curving radially inward, covering the inner accommodating portion 64b from the front side in the rotational direction. The end of the covering portion 267 on the rear side in the rotational direction (−θ side) is connected to the radially outer end of the inner end of the extension direction of the first accommodating portion 64a.
[0071] As shown in FIG. 11 , the lower end of the covering portion 267 is located lower than the lower end of the inner accommodating portion 64b. The lower end of the covering portion 267 is located at the same position in the vertical direction Z as the lower end of the inner portion 64d of the first accommodating portion 64a. As shown in FIG. 12 , the covering portion 267 is connected to the radially outer side of the inner accommodating portion 64b. A portion of the covering portion 267 forms a radially outer wall portion of the inner accommodating portion 64b. The upper end of the covering portion 267 is located lower as it moves radially inward along the outer surface of the shroud main body 62a. The dimension of the covering portion 267 in the vertical direction Z decreases as it moves radially inward.
[0072] Other configurations of the shroud portion 262 are similar to other configurations of the shroud portion 62 in embodiment 1. Other configurations of the impeller 260 are similar to other configurations of the impeller 260 in embodiment 1.
[0073] According to the second embodiment, the shroud portion 262 has a covering portion 267 that protrudes downward from the shroud main body portion 62a. The lower end of the covering portion 267 is located lower than the lower end of the inner accommodating portion 64b. The covering portion 267 extends from the radially outer side of the inner accommodating portion 64b toward the front side (+θ side) in the rotational direction while curving radially inward, covering the inner accommodating portion 64b from the front side in the rotational direction. Therefore, when the impeller 260 rotates, the covering portion 267 can deflect air from the front side in the rotational direction, thereby preventing air from colliding with the inner accommodating portion 64b from the front side in the rotational direction. This reduces noise generated when the impeller 260 rotates.
[0074] Furthermore, according to the second embodiment, the covering portion 267 is connected to the radially outer side of the inner accommodating portion 64b. Therefore, it is easier to manufacture the covering portion 267 together with the inner accommodating portion 64b than if the covering portion 267 were manufactured separately from the inner accommodating portion 64b. This makes it easier to manufacture the covering portion 267.
[0075] Embodiment 3. Figure 13 is a perspective view showing a part of an impeller 360 in embodiment 3. Figure 14 is a cross-sectional view showing a part of an impeller 360 in embodiment 3. Figure 15 is a perspective view showing a part of a blade portion 363 in embodiment 3. In the following description, the same components as those in the above-described embodiments will be denoted by the same reference numerals as appropriate, and description thereof may be omitted.
[0076] As shown in Figures 13 and 14, the protruding accommodating portion 364 in the shroud portion 362 of the third embodiment has, as a second accommodating portion, an outer accommodating portion 364i that connects to the radially outer end of the first accommodating portion 64a in the extension direction. The outer accommodating portion 364i connects to the outer end of the outer portion 64c in the extension direction. The outer accommodating portion 364i extends in the extension direction and has a generally rectangular box shape that opens upward. The lower end of the outer accommodating portion 364i is located above the lower end of the outer portion 64c of the first accommodating portion 64a. The other configurations of the shroud portion 362 are similar to those of the shroud portion 62 of the first embodiment.
[0077] 14 and 15 , the protrusion 366 of the blade 363 of the third embodiment has, as a second protrusion, an outer protrusion 366i that connects to the radially outer end of the first protrusion 66a in the extension direction. The outer protrusion 366i connects to the outer end of the outer portion 66c in the extension direction. The outer protrusion 366i has a generally rectangular parallelepiped shape that extends in the extension direction. In the third embodiment, the outer protrusion 366i is a solid portion.
[0078] As shown in Figure 14, the outer protrusion 366i is accommodated within the outer accommodating portion 364i. The lower end of the outer protrusion 366i is located higher than the lower end of the outer portion 66c of the first protrusion 66a. The outer protrusion 366i faces a lower surface of the inner surface of the outer accommodating portion 364i across a gap. The other configurations of the blade portion 363 are the same as the other configurations of the blade portion 63 in embodiment 1. The other configurations of the impeller 360 are the same as the other configurations of the impeller 60 in embodiment 1.
[0079] According to the third embodiment, the protruding accommodating portion 364 has, as a second accommodating portion, an outer accommodating portion 364i that connects to the radially outer end of the first accommodating portion 64a in the extension direction. The protruding portion 366 has, as a second convex portion, an outer convex portion 366i that connects to the radially outer end of the first accommodating portion 66a in the extension direction. The outer convex portion 366i is accommodated within the outer accommodating portion 364i. This prevents air from flowing from the positive pressure side to the negative pressure side on the outer side of the extension direction of the first accommodating portion 66a. This more effectively prevents a decrease in the air blowing efficiency of the impeller 360.
[0080] Embodiment 4. Figure 16 is a perspective view showing a part of an impeller 460 in embodiment 4. In the following description, the same components as those in the above-described embodiments will be denoted by the same reference numerals as appropriate, and the description may be omitted.
[0081] As shown in Fig. 16, the shroud portion 462 of the impeller 460 in the fourth embodiment is configured by providing the covering portion 267 in the second embodiment to the shroud portion 362 in the third embodiment described above. Although not shown, the blade portion in the fourth embodiment is similar to the blade portion 363 in the third embodiment. As a result, according to the fourth embodiment, it is possible to obtain the effects described in the second and third embodiments. The other configurations of the impeller 460 are similar to the other configurations of the impeller 60 in the first embodiment.
[0082] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the configurations of the above-described embodiments, and the following configurations and methods may also be adopted.
[0083] The protruding accommodating portion in the shroud portion may have at least one of an inner accommodating portion and an outer accommodating portion as the second accommodating portion. That is, the protruding accommodating portion in the shroud portion may have only an outer accommodating portion as the second accommodating portion. For example, in the above-described third and fourth embodiments, the inner accommodating portion 64b may not be provided. The protruding height of the second accommodating portion is not particularly limited. The end of the first side (lower side) of the second accommodating portion may be located at the same position in the axial direction (vertical direction Z) as the portion of the first accommodating portion located closest to the first side, or may be located closer to the first side than the portion of the first accommodating portion located closest to the first side. The second accommodating portion may have any shape as long as it can accommodate the second protrusion.
[0084] The first receiving portion of the protruding receiving portion may have any shape as long as it can receive the first convex portion. In each of the above-described embodiments, the first receiving portion 64a has an outer portion 64c and an inner portion 64d that have different protruding heights, but this is not limited to this. The first receiving portion may have no portions with different protruding heights, or may have three or more portions with different protruding heights.
[0085] The protruding portion of the blade portion may have at least one of an inner protrusion and an outer protrusion as the second protrusion. In other words, the protruding portion of the blade portion may have only an outer protrusion as the second protrusion. For example, in the above-described third and fourth embodiments, the inner protrusion 66b may not be provided. The protruding height of the second protrusion is not particularly limited. The end of the first side (lower side) of the second protrusion may be located at the same position in the axial direction (vertical direction Z) as the portion of the first protrusion located closest to the first side, or may be located closer to the first side than the portion of the first protrusion located closest to the first side. The second protrusion may have any shape. For example, the shape of the inner protrusion 66b in each of the above-described embodiments may be the same as the shape of the outer protrusion 366i in the third embodiment. The second protrusion may have a portion that contacts the inner surface of the second housing portion, as long as it faces the surface of the inner surface of the second housing portion located closest to the first side across a gap.
[0086] The first protrusion of the protrusion may have any shape as long as it can be fixed to the first housing portion. In each of the above-described embodiments, the first protrusion 66a has an outer portion 66c and an inner portion 66d that have different protruding heights, but this is not limited to this. The first protrusion may have no portions with different protruding heights, or may have three or more portions with different protruding heights. A portion of the first protrusion other than the portion fixed to the first housing portion may contact the inner surface of the first housing portion. The first protrusion may be fixed to the shroud portion by a method other than laser welding.
[0087] The covering portion of the shroud portion does not have to be connected to the inner housing portion or the first housing portion. The number of blade portions and the number of protruding housing portions of the shroud portion are not particularly limited. The shape of the blade main body portion is not particularly limited. The blade main body portion may extend in any manner when viewed in the axial direction (vertical direction Z). The positional relationship between the first blade member and the second blade member constituting the blade portion may be the opposite of the positional relationship in the above-described embodiment. In other words, the second blade member may face the negative pressure side. Each blade portion may be an integrally molded solid blade portion. The axial direction of the rotation shaft of the impeller of the present disclosure is not particularly limited and may extend in a direction other than the vertical direction. The impeller of the present disclosure may be mounted in any type of blower. The centrifugal blower of the present disclosure may be mounted in any type of equipment.
[0088] The configurations and methods described in this specification can be combined as appropriate within the scope of not contradicting each other.
[0089] DESCRIPTION OF SYMBOLS 10... Indoor unit, 14... Heat exchanger, 40... Centrifugal blower, 50... Drive unit, 60, 260, 360, 460, 560... Impeller, 61... Base, 62, 262, 362, 462, 562... Shroud portion, 62a... Shroud main body portion, 63, 363, 563... Blade portion, 64, 364, 564... Protruding accommodating portion, 64a... First accommodating portion, 64b... Inner accommodating portion (second accommodating portion), 65... Blade main body portion, 66, 366, 566... Protruding portion, 66a... First convex portion, 66b... Inner convex portion (second convex portion), 100... Air conditioner, 267... Covering portion, 364i... Outer accommodating portion, 366i... Outer convex portion, R... Rotation axis, Z... Vertical direction (axial direction)
Claims
1. An impeller rotatable around a rotation axis, comprising: a base; a shroud portion located on a first side of the base in the axial direction of the rotation axis; and a plurality of blade portions located axially between the base and the shroud portion and spaced apart in the rotation direction of the impeller, wherein the shroud portion has: a shroud main body portion; and a plurality of protruding accommodating portions that protrude from the shroud main body portion to the first side and open to a second side opposite to the first side in the axial direction, wherein each of the plurality of blade portions has: a blade main body portion; and a protruding portion that protrudes from the blade main body portion to the first side, wherein one end of the blade main body portion in an extension direction in which the blade main body portion extends as viewed in the axial direction is located radially inward about the rotation axis than the other end of the blade main body portion in the extension direction, and the protruding portions of the plurality of blade portions are respectively accommodated in the plurality of protruding accommodating portions, and each of the plurality of protruding accommodating portions is an impeller having a first accommodating portion and a second accommodating portion connected to an end of the first accommodating portion in the extension direction, wherein the protrusion has: a first convex portion housed in the first accommodating portion and fixed to the shroud portion; and a second convex portion connected to an end of the first convex portion in the extension direction and housed in the second accommodating portion, wherein the first convex portion is fixed in contact with a surface of an inner surface of the first accommodating portion that is located on the first side, and the second convex portion faces a surface of an inner surface of the second accommodating portion that is located on the first side across a gap.
2. An impeller as described in claim 1, wherein each of the plurality of protruding accommodating portions has, as the second accommodating portion, an inner accommodating portion connected to one of the ends of the first accommodating portion in the extension direction that is located radially inward, and the protruding portion has, as the second convex portion, an inner convex portion connected to one of the ends of the first convex portion in the extension direction that is located radially inward, and the inner convex portion is accommodated within the inner accommodating portion.
3. An impeller as set forth in claim 2, wherein one end of the blade main body portion in the extension direction is located radially inward and forward in the rotational direction than the other end of the blade main body portion in the extension direction, the shroud portion has a covering portion protruding from the shroud main body portion to the first side, the first side end of the covering portion is located on the first side than the first side end of the inner accommodating portion, and the covering portion extends from the radially outer side of the inner accommodating portion to the forward side in the rotational direction while curving radially inward, so as to cover the inner accommodating portion from the forward side in the rotational direction.
4. The impeller according to claim 3, wherein the covering portion is connected to the radially outer side of the inner accommodating portion.
5. An impeller as described in any one of claims 1 to 4, wherein the protruding accommodating portion has, as the second accommodating portion, an outer accommodating portion connected to one of the two end portions of the first accommodating portion in the extension direction that is located radially outward, and the protruding portion has, as the second convex portion, an outer convex portion connected to one of the two end portions of the first convex portion in the extension direction that is located radially outward, and the outer convex portion is accommodated within the outer accommodating portion.
6. An impeller as described in any one of claims 1 to 5, wherein the first side end of the second accommodating portion is located on the second side of the portion of the first accommodating portion that is located furthest on the first side, and the first side end of the second convex portion is located on the second side of the portion of the first convex portion that is located furthest on the first side.
7. An impeller according to any one of claims 1 to 6, wherein the entire second protrusion is positioned away from the inner surface of the second accommodating portion.
8. An impeller described in any one of claims 1 to 7, wherein the end of the second convex portion in the extension direction opposite to the side connected to the first convex portion is connected without a step to the end of the blade main body portion in the extension direction.
9. A centrifugal blower comprising: an impeller according to any one of claims 1 to 8; and a drive unit that rotates the impeller around the rotation axis.
10. An indoor unit for an air conditioner, comprising: the centrifugal blower according to claim 9; and a heat exchanger to which air is blown by the centrifugal blower.