Centrifugal blower and indoor unit

Abstract

One aspect of a centrifugal blower according to the present disclosure comprises a drive unit having a rotating shaft that rotates about an axis of rotation, and an impeller that is disposed on one side in the axial direction of the axis of rotation with respect to the drive unit and is rotated by the drive unit around the axis of rotation to the front side in the rotation direction, wherein: the impeller includes a main plate fixed to the rotating shaft, an annular shroud facing the main plate in the axial direction, and a plurality of vane parts connecting the main plate and the shroud; the main plate has a hub covering the drive unit from one side in the axial direction and the radially outside of the axis of rotation; the hub has a plurality of guide parts that protrude radially outward and are aligned in the rotation direction; air holes that open to the radially outside are formed in the plurality of guide parts; and the outer circumferential surface of the plurality of guide parts has a pair of circumferential surface parts that are respectively positioned on the front side and rear side in the rotation direction with respect to the air holes, and that face radially outward.

Description

Technical Field

[0001] The present disclosure relates to a centrifugal blower and an indoor unit.

Background Art

[0002] Among the indoor units of air conditioners, the ceiling-embedded type has a suction port and a blowout port formed on the lower surface of the device facing the air-conditioned room. Then, the air sucked into the case from the suction port is temperature-adjusted by the heat exchanger in the case and then sent out from the blowout port to the room. The above-described air flow of the indoor unit is created by a centrifugal blower that sucks air upward from below and turns the flow radially outward to blow out the air. The centrifugal blower has a shroud, a main board, and a plurality of blade parts connecting between the shroud and the main board. In such a centrifugal blower, a main flow directed radially outward is formed between the main board and the shroud.

[0003] Patent Document 1 discloses a structure in which, in addition to the above-described main flow, a sub-flow directed radially inward is generated above the main board to cool the fan motor. In the centrifugal blower of Patent Document 1, by setting the blowout direction of the sub-flow to the rear side in the rotation direction of the main board by the air guide part, generation of noise associated with the confluence of the sub-flow and the main flow is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the indoor unit as described above, the flow path resistance of the sub-flow has increased because the flow direction of the air in the sub-flow is sharply bent. For this reason, in the conventional structure, there has been a problem that the air volume of the sub-flow decreases and the cooling efficiency of the fan motor tends to deteriorate.

[0006] In view of the above circumstances, one of the objectives of the present disclosure is to provide a centrifugal blower and an indoor unit that can sufficiently ensure the flow rate of the sub-flow while suppressing noise.

Means for Solving the Problem

[0007] One aspect of the centrifugal blower according to the present disclosure includes a drive unit having a rotating shaft that rotates about a rotation axis, and an impeller that is disposed on one axial side of the rotation axis with respect to the drive unit and is rotated forward in the rotation direction around the rotation axis by the drive unit. The impeller includes a main plate fixed to the rotating shaft, an annular shroud facing the main plate in the axial direction, and a plurality of blade portions connecting the main plate and the shroud. The main plate has a hub that covers the drive unit from one axial side and the radially outer side of the rotation axis. The hub has a plurality of guide portions that protrude radially outward and are arranged in the rotation direction. Air holes that open radially outward are formed in the plurality of guide portions. The outer peripheral surface of the plurality of guide portions has a first circumferential surface that is located on the front side in the rotation direction with respect to the air holes and faces radially outward, and a second circumferential surface that is located on the rear side in the rotation direction with respect to the air holes and faces radially outward. The second circumferential surface extends in the rotation direction and is arranged continuously with the opening of the air holes in the rotation direction. The first circumferential surface and the second circumferential surface are curved surfaces that curve around the rotation axis, respectively.

[0008] One aspect of the indoor unit according to the present disclosure includes the above centrifugal blower and a heat exchanger disposed around the centrifugal blower.

Advantages of the Invention

[0009] According to the present disclosure, a centrifugal blower and an indoor unit that can sufficiently ensure the flow rate of the sub-flow while suppressing noise are provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

MODE FOR CARRYING OUT THE INVENTION

[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 arbitrarily changed within the scope of the technical idea of the present disclosure. Also, in the following drawings, in order to make each configuration easy to understand, the scale and number in each structure may be different from those in the actual structure.

[0012] Also, in the drawings, a Z-axis indicating the vertical direction is shown as appropriate. Among the vertical directions, the side toward which the arrow of the Z-axis points (+Z side) is the upper side, and the side opposite to the side toward which the arrow of the Z-axis points in the vertical direction Z (-Z side) is the lower side. Note that the posture of the indoor unit 10 described in the present embodiment with respect to the vertical direction is merely an example and does not limit the installation posture of the indoor unit 10.

[0013] FIG. 1 is a schematic diagram showing a schematic configuration of an air conditioner 100 in the present embodiment. As shown in FIG. 1, the air conditioner 100 includes an indoor unit 10, an outdoor unit 20, and a circulation path unit 30. The indoor unit 10 is arranged indoors. The outdoor unit 20 is arranged outdoors. The indoor unit 10 and the outdoor unit 20 are connected to each other by a circulation path unit 30 through which a refrigerant 33 circulates. The indoor unit 10 and the outdoor unit 20 are heat exchange units that perform heat exchange with air.

[0014] The air conditioner 100 can adjust the temperature of the indoor air by performing heat exchange between the refrigerant 33 flowing in the circulation path section 30 and the indoor air where the indoor unit 10 is disposed. Examples of the refrigerant 33 include a fluorine-based refrigerant having a low global warming potential (GWP) or a hydrocarbon-based refrigerant.

[0015] The outdoor unit 20 includes a compressor 21, an outdoor heat exchanger 23, a flow rate adjustment valve 24, a blower 25, and a four-way valve 22. The compressor 21, the outdoor heat exchanger 23, the flow rate adjustment valve 24, and the four-way valve 22 are connected by the circulation path section 30.

[0016] The four-way valve 22 is disposed at 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 in the circulation path section 30 by switching a part of the path of the circulation path section 30. When the path connected by the four-way valve 22 is the path indicated by the solid line in the four-way valve 22 of FIG. 1, the refrigerant 33 flows in the circulation path section 30 in the direction indicated by the solid line arrow in FIG. 1. On the other hand, when the path connected by the four-way valve 22 is the path indicated by the broken line in the four-way valve 22 of FIG. 1, the refrigerant 33 flows in the circulation path section 30 in the direction indicated by the broken line arrow in FIG. 1.

[0017] The indoor unit 10 includes a centrifugal blower 40 and an indoor heat exchanger (heat exchanger) 14 disposed around the centrifugal blower. The indoor unit 10 can perform a cooling operation for cooling the indoor air where the indoor unit 10 is disposed and a heating operation for heating the indoor air where the indoor unit 10 is disposed.

[0018] When the indoor unit 10 is in the cooling operation, the refrigerant 33 flowing in the circulation path section 30 flows in the direction indicated by the solid arrow in FIG. 1. That is, when the indoor unit 10 is in the cooling operation, the refrigerant 33 flowing in the circulation path section 30 circulates through the compressor 21, the outdoor heat exchanger 23 of the outdoor unit 20, the flow rate adjustment valve 24, and the indoor heat exchanger 14 of the indoor unit 10 in this order and returns to the compressor 21. In the cooling operation, the outdoor heat exchanger 23 in the outdoor unit 20 functions as a condenser, and the indoor heat exchanger 14 in the indoor unit 10 functions as an evaporator.

[0019] On the other hand, when the indoor unit 10 is in the heating operation, the refrigerant 33 flowing in the circulation path section 30 flows in the direction indicated by the broken line in FIG. 1. That is, when the indoor unit 10 is in the heating operation, the refrigerant 33 flowing in the circulation path section 30 circulates through the compressor 21, the indoor heat exchanger 14 of the indoor unit 10, the flow rate adjustment valve 24, and the outdoor heat exchanger 23 of the outdoor unit 20 in this order and returns to the compressor 21. In the heating operation, the outdoor heat exchanger 23 in the outdoor unit 20 functions as an evaporator, and the indoor heat exchanger 14 in the indoor unit 10 functions as a condenser.

[0020] Next, the indoor unit 10 of the present embodiment will be described in more detail. FIG. 2 is a perspective view showing the indoor unit 10. FIG. 3 is a schematic cross-sectional view showing the indoor unit 10. In each of the figures after FIG. 3, the rotation axis line R is shown as appropriate. The rotation axis line R is an imaginary line passing through the center of the centrifugal blower 40 in the following embodiments. The impeller 60 of the centrifugal blower 40 rotates about the rotation axis line R. The direction in which the rotation axis line R of the present embodiment extends is the vertical direction.

[0021] In the following description, the axial direction of the rotation axis R, that is, the direction parallel to the Z-axis, is simply referred to as the "axial direction", the radial direction centered on the rotation axis R is simply referred to as the "radial direction", and the circumferential direction centered on the rotation axis R may be simply referred to as the "circumferential direction". Further, in the following description, the lower side in the vertical direction (-Z side) may be referred to as one side in the axial direction, and the upper side in the vertical direction (+Z side) may be referred to as the other side in the axial direction. Furthermore, in the following description, "radially outer" means the side away from the rotation axis R in the radial direction, and "radially inner" means the side opposite to the radially outer side in the radial direction and approaching the rotation axis R.

[0022] The indoor unit 10 of the present embodiment is a ceiling-embedded type indoor unit installed by being embedded in the ceiling. As shown in FIG. 3, the indoor unit 10 includes a housing 11 in addition to a centrifugal blower 40 and an indoor heat exchanger 14. The housing 11 includes a housing main body portion 12 that covers the centrifugal blower 40 and the indoor heat exchanger 14 from above, and a decorative panel 13 located below the centrifugal blower 40 and the indoor heat exchanger 14. The housing main body portion 12 has a flat plate-shaped top plate portion 12a orthogonal to the rotation axis R. The indoor heat exchanger 14 and the centrifugal blower 40 are fixed to the lower surface of the top plate portion 12a. Further, a suction port 10a and a blowout port 10b are formed in the decorative panel 13.

[0023] The centrifugal blower 40 has a drive unit 50 and an impeller 60. The drive unit 50 is, for example, a fan motor. The drive unit 50 has a drive unit main body 51 and a rotating shaft 52. The drive unit main body 51 is fixed to the top plate portion 12a of the housing 11. The rotating shaft 52 rotates about the rotation axis R. The impeller 60 is disposed below (one side in the axial direction) with respect to the drive unit 50. The impeller 60 is rotated around the rotation axis R by the drive unit 50.

[0024] When the drive unit 50 drives and the impeller 60 rotates, the air in the room where the indoor unit 10 is installed is sucked into the interior of the indoor unit 10 through the suction port 10a. The air sucked into the interior of the indoor unit 10 is further sucked into the impeller 60 through the intake port 60a of the impeller 60. The air sucked into the impeller 60 flows radially outward inside the impeller 60 as the blades 63 of the impeller 60 rotate, and is blown out of the centrifugal blower 40 through the exhaust port facing the radially outer side. The air blown out from the centrifugal blower 40 passes through the indoor heat exchanger 14, is heat-exchanged and humidity-adjusted during passage, then changes its flow direction downward, and is blown out into the room through the blowout port 10b.

[0025] Here, the air flow generated by the centrifugal blower 40 will be described. The centrifugal blower 40 generates a main flow AF and a sub-flow BF inside the indoor unit 10.

[0026] The main flow AF is the air flow that flows into the impeller 60 from the intake port 60a, passes through the space between the main board 61 and the shroud 62 toward the radially outer side, and is blown out from the exhaust port 60b to the indoor heat exchanger 14 on the radially outer side. The main flow AF is formed to allow the indoor air to pass through the indoor heat exchanger 14 and return to the room again.

[0027] The sub-flow BF branches off from the main flow AF at the exhaust port 60b, passes through the upper side of the impeller 60 (between the main board 61 and the top plate portion 12a), flows downward around the drive unit 50, and merges with the main flow AF through the air hole 61f formed in the main board 61. The sub-flow BF takes heat away from the drive unit 50 and cools the drive unit 50 when passing around the drive unit 50. Therefore, the cooling efficiency of the drive unit 50 can be improved by ensuring a sufficient flow rate of the sub-flow BF.

[0028] Next, the impeller 60 of the present embodiment will be described in detail. FIG. 4 is a perspective view of the impeller 60. In each figure after FIG. 4, the rotation direction T of the impeller 60 is illustrated by an arrow. In the present embodiment, the rotation direction T is the counterclockwise direction when the impeller 60 is viewed from below in the circumferential direction. In the following description, the direction toward the rotation direction T may be referred to as the front side of the rotation direction T, and the direction opposite to this front side may be referred to as the rear side of the rotation direction T. The impeller 60 is rotated in the front side of the rotation direction T by the drive unit 50.

[0029] The impeller 60 includes a main plate 61, a shroud 62, and a plurality of blade parts 63. The main plate 61, the shroud 62, and the blade parts 63 are each made of a resin material. The main plate 61, the shroud 62, and the blade parts 63 are fixed to each other and rotate around the rotation axis R.

[0030] The main plate 61 is fixed to the rotating shaft 52 (see FIG. 3) of the drive unit 50. The main plate 61 is rotated around the rotation axis R by the drive unit 50. The main plate 61 has a hub 61b, a shaft holding part 61e, and a base 61a.

[0031] The hub 61b bulges downward (on one side in the axial direction) at the central part of the main plate 61 (the rotation axis R of the centrifugal blower 40 and its vicinity). The hub 61b covers the drive unit 50 from below (on one side in the axial direction) and from the radially outer side. That is, an accommodation space for accommodating the drive unit 50 is formed inside the hub 61b in the radial direction.

[0032] The hub 61b has a diameter that decreases towards the lower side. The hub 61b has a flat plate portion 61d and a conical portion 61c. The flat plate portion 61d is located below the drive portion 50. The flat plate portion 61d is in the shape of a flat plate that is highly effective with respect to the rotation axis R. The flat plate portion 61d is circular in plan view. The conical portion 61c extends upward from the outer edge of the flat plate portion 61d. The conical portion 61c is conical and expands radially outward as it goes upward. The conical portion 61c surrounds the drive portion 50 from the radially outer side. A curved portion 61ca that is smoothly connected to the flat plate portion 61d is formed at the lower end portion of the conical portion 61c. The conical portion 61c curves with a certain curvature at the curved portion 61ca. The conical portion 61c gradually increases its inclination as it goes upward from the flat plate portion 61d at the curved portion 61ca. Also, the conical portion 61c has a certain inclination in the region above the curved portion 61ca.

[0033] The hub 61b has a plurality (seven in this embodiment) of guide portions 70 that project radially outward. In this embodiment, the guide portions 70 are formed at the curved portion 61ca of the conical portion 61c. That is, the guide portions 70 project radially outward from the outer peripheral surface of the curved portion 61ca. The plurality of guide portions 70 are arranged at intervals in the rotational direction of the rotation axis R. One air hole 61f is formed in each of the guide portions 70. The air hole 61f guides air from the radially inner space of the hub 61b to the radially outer space. The guide portions 70 will be described in more detail later.

[0034] The shaft holding portion 61e is arranged at the center of the flat plate portion 61d of the hub 61b. The shaft holding portion 61e is cylindrical with the rotation axis R as the center. The rotating shaft 52 is arranged inside the shaft holding portion 61e. Also, a connecting member 53 is fixed to the inner peripheral surface of the shaft holding portion 61e. The connecting member 53 connects the outer peripheral surface of the rotating shaft 52 and the inner peripheral surface of the shaft holding portion 61e.

[0035] The base 61a extends radially outward from the upper end of the hub 61b. The base 61a is in the shape of a flat plate extending along a plane orthogonal to the rotation axis R. The base 61a is an annular portion whose outer peripheral edge is circular in plan view.

[0036] The upper surface of the base 61a (the surface facing the other axial side) faces the top plate portion 12a of the housing 11 with a gap therebetween. A sub-flow BF flows in the gap between the upper surface of the base 61a and the top plate portion 12a. An upper support portion 61p to which a plurality of blade portions 63 are fixed by fixing means such as welding is formed on the lower surface of the base 61a (the surface facing one axial side).

[0037] The shroud 62 is an annular plate-like member. The shroud 62 faces the main plate 61 in the axial direction. A gap through which the main flow AF flows is formed between the main plate 61 and the shroud 62. The inner edge of the shroud 62 protrudes downward in a cylindrical shape to form an air intake port 60a that guides air into the main flow AF.

[0038] A lower support portion 62p to which a plurality of blade portions 63 are fixed by fixing means such as welding is formed on the shroud 62. The lower support portion 62p has a recess that is recessed downward and into which the blade portions 63 are inserted, and the blade portions 63 are fixed within the recess.

[0039] The plurality of blade portions 63 connect the main plate 61 and the shroud 62. That is, a plurality (seven in the present embodiment) of blade portions 63 are arranged between the main plate 61 and the shroud 62. The blade portions 63 are hollow plate-like and extend along the rotation axis R. The blade portions 63 are welded and fixed to the shroud 62 at the lower end portions and to the main plate 61 at the upper end portions.

[0040] The blade portions 63 are inclined toward the rear side in the rotation direction T as they extend from the radially inner side to the radially outer side. The plurality of blade portions 63 push the air between the main plate 61 and the shroud 62 radially outward as the impeller 60 rotates around the rotation axis R. Thereby, the impeller 60 forms a main flow AF that sends air from the air intake port 60a to the exhaust port 60b.

[0041] Next, the guide portion 70 of the present embodiment will be described in detail. FIG. 5 is a perspective view of the vicinity of the lower end of the hub 61b. FIG. 6 is a plan view of the guide portion 70. FIG. 7 is a cross-sectional view of the guide portion 70 taken along line VII-VII of FIG. 6.

[0042] As shown in FIG. 5, the air hole 61f formed in the guide portion 70 penetrates the hub 61b in the thickness direction. The air hole 61f opens toward the radially outer side. The air hole 61f is substantially rectangular when viewed from the opening direction. Note that the opening direction of the air hole 61f only needs to have a component directed toward the radially outer side, and does not necessarily exactly coincide with the radial direction in a strict sense.

[0043] According to the present embodiment, since the air hole 61f opens toward the radially outer side, the air of the sub-flow BF flowing downward in the space radially inside the hub 61b can be smoothly guided to the radially outer side of the hub 61b. Therefore, the flow path resistance of the sub-flow BF can be suppressed, the flow rate of the sub-flow BF can be increased, and the cooling efficiency of the drive portion 50 can be increased.

[0044] As shown in FIG. 6, the outer peripheral surface 70a of the guide portion 70 has a first circumferential surface (circumferential surface) 72, a second circumferential surface (circumferential surface) 73, a third circumferential surface 74, a flange surface 75, a connection surface 76, a front side surface 77, and a rear side surface 78.

[0045] The first circumferential surface 72, the second circumferential surface 73, and the third circumferential surface 74 are surfaces facing the radially outer side. The first circumferential surface 72, the second circumferential surface 73, and the third circumferential surface 74 each extend in the rotational direction. The first circumferential surface 72, the second circumferential surface 73, and the third circumferential surface 74 are curved surfaces that gently curve around the rotation axis R.

[0046] The first circumferential surface 72 is located on the front side in the rotational direction T with respect to the air hole 61f. On the other hand, the second circumferential surface 73 is located on the rear side in the rotational direction T with respect to the air hole 61f. That is, the outer peripheral surface 70a of the guide portion 70 has a pair of circumferential surfaces 72 and 73 that are respectively located on the front side and the rear side in the rotational direction T with respect to the air hole 61f.

[0047] The guide portion 70 of the present embodiment has a first circumferential surface 72 and a second circumferential surface 73 that are respectively arranged on both sides in the rotational direction (i.e., both sides in the circumferential direction) of the air hole 61f. Thereby, the main flows AF flowing on one side and the other side in the circumferential direction of the guide portion 70 can be passed through while being separated in the circumferential direction from the air hole 61f. The air of the sub-flow BF blown out from the air hole 61f merges with the main flow AF in a sufficiently diffused state. As a result, the generation of turbulent flow at the confluence of the sub-flow BF and the main flow AF can be suppressed, and the noise associated with the confluence can be suppressed.

[0048] The lengths d1 and d2 in the rotational direction of the first circumferential surface 72 and the second circumferential surface 73 (a pair of circumferential surfaces located on both sides in the rotational direction of the air hole 61f) are preferably smaller than the length D in the rotational direction of the air hole 61f, respectively. In order to reduce the flow resistance of the sub-flow BF and increase the flow rate of the sub-flow BF, it is preferable to make the length D in the rotational direction of the air hole 61f as large as possible. On the other hand, by increasing the lengths d1 and d2 in the rotational direction of the first circumferential surface 72 and the second circumferential surface 73, it becomes easier to suppress the noise at the confluence of the sub-flow BF and the main flow AF. However, if the lengths d1 and d2 in the rotational direction of the first circumferential surface 72 and the second circumferential surface 73 are increased too much, the circumferential dimension of the guide portion 70 will increase, and there is a risk of obstructing the flow along the outer peripheral surface of the hub 61b of the main flow AF. According to the present embodiment, by making the lengths d1 and d2 in the rotational direction of the first circumferential surface 72 and the second circumferential surface 73 smaller than the length D in the rotational direction of the air hole 61f, it is possible to suppress the guide portion 70 from becoming too large while ensuring the flow rate of the sub-flow BF.

[0049] The first circumferential surface portion 72 is a surface formed on the surface of the convex portion 71 that protrudes radially outward with respect to the opening 61fa of the air hole 61f. Therefore, the first circumferential surface portion 72 is arranged radially outside the opening 61fa of the air hole 61f. In addition, in this specification, the opening 61fa of the air hole 61f means a region surrounded by the edge on the outer side in the penetrating direction of the air hole 61f.

[0050] When the impeller 60 rotates, the guide portion 70 rotates relative to the air inside the impeller 60. For this reason, a relative air flow (hereinafter referred to as a swirling flow CF) that heads toward the opposite side of the rotation direction T of the impeller 60 is generated around the guide portion 70.

[0051] According to the present embodiment, the first circumferential surface portion 72 located on the front side in the rotation direction T with respect to the air hole 61f is arranged radially outside the opening 61fa of the air hole 61f. The swirling flow CF is deflected by the convex portion 71 on the front side in the rotation direction T of the air hole 61f and flows in the circumferential direction along the first circumferential surface portion 72. According to the present embodiment, since the first circumferential surface portion 72 is located radially outside the opening 61fa of the air hole 61f, the swirling flow CF can be passed radially outside the opening 61fa of the air hole 61f. Thereby, it is possible to suppress the sub-flow BF blown out from the air hole 61f from colliding with the swirling flow CF, suppress the generation of turbulent flow when the sub-flow BF and the swirling flow CF merge, and suppress the noise associated with the merger. In addition, by passing the swirling flow CF away from the air hole 61f, it is possible to suppress the air of the swirling flow CF from flowing into the air hole 61f and ensure the flow rate of the sub-flow BF blown out from the air hole 61f. Furthermore, it is possible to suppress the swirling flow CF from colliding with the edge of the air hole 61f and suppress the generation of noise associated with the vibration of the edge.

[0052] The second circumferential surface portion 73 is arranged continuously with the opening 61fa of the air hole 61f. Therefore, the radial position of the opening 61fa of the air hole 61f and the radial position of the second circumferential surface portion 73 coincide with each other. Also, the second circumferential surface portion 73 is arranged radially inside the first circumferential surface portion 72.

[0053] According to the present embodiment, the second circumferential surface portion 73 on the rear side in the rotation direction T of the air hole 61f does not protrude with respect to the opening 61fa of the air hole 61f. Therefore, the air blown out from the air hole 61f can smoothly flow to the rear side in the rotation direction T, and smooth confluence of the swirling flow CF and the sub-flow BF can be promoted.

[0054] The third circumferential surface portion 74 is located below the air hole 61f (on one side in the axial direction). The third circumferential surface portion 74 is arranged continuously with the opening 61fa of the air hole 61f. Therefore, the second circumferential surface portion 73 and the third circumferential surface portion 74 are arranged continuously with each other in the rotation direction.

[0055] The eaves surface portion 75 is located below the air hole 61f (on one side in the axial direction). Also, the eaves surface portion 75 faces downward (on one side in the axial direction). The eaves surface portion 75 is a surface extending in the rotation direction. The entire rotation direction of the eaves surface portion 75 includes the entire rotation direction of the air hole 61f. That is, one end portion in the circumferential direction of the eaves surface portion 75 is located on the one side in the circumferential direction from one end portion in the circumferential direction of the air hole 61f, and the other end portion in the circumferential direction of the eaves surface portion 75 is located on the other side in the circumferential direction from the other end portion in the circumferential direction of the air hole 61f. The eaves surface portion 75 is connected to the first circumferential surface portion 72, the second circumferential surface portion 73, and the third circumferential surface portion 74 via corner portions.

[0056] As shown in FIG. 7, a part of the main flow AF flowing radially outward along the outer peripheral surface of the hub 61b hits the guide portion 70 and passes below the eaves surface portion 75 and radially outside the third circumferential surface portion 74. According to the present embodiment, by arranging the third circumferential surface portion 74 below the air hole 61f (on one side in the axial direction), the main flow AF flowing below the eaves surface portion 75 can be passed axially spaced from the opening 61fa of the air hole 61f. Thereby, collision at the time of confluence of the main flow AF and the sub-flow BF can be suppressed and they can be smoothly confluent.

[0057] According to this embodiment, the main flow AF flowing upward toward the guide portion 70 hits the eaves portion 75 located below the air hole 61f and facing downward, and the flow direction changes radially outward. As a result, the main flow AF can be suppressed from flowing into the air hole 61f opening radially outward, and the flow rate of the sub-flow BF can be ensured. Further, the main flow AF can be suppressed from colliding with the edge of the air hole 61f, and noise generation due to vibration of the edge can be suppressed.

[0058] As shown in FIG. 6, the front side surface portion 77 faces the front side in the rotation direction T. The front side surface portion 77 is a surface extending in the radial direction. The front side surface portion 77 is located on the front side in the rotation direction T with respect to the first circumferential surface portion 72. The front side surface portion 77 receives the turning flow CF.

[0059] The connection surface portion 76 connects the first circumferential surface portion 72 and the front side surface portion 77. The connection surface portion 76 is on the front side in the rotation direction T and faces a direction slightly inclined radially outward with respect to the front side in the rotation direction T. The connection surface portion 76 is a surface formed on the surface of the convex portion 71. The connection surface portion 76 is inclined radially inward as it extends from the first circumferential surface portion 72 toward the front side surface portion 77.

[0060] The turning flow CF hits the front side surface portion 77, changes the flow direction radially outward, and flows along the first circumferential surface portion 72. According to this embodiment, since the connection surface portion 76 connecting the first circumferential surface portion 72 and the front side surface portion 77 is formed on the outer peripheral surface of the guide portion 70, the turning flow CF hitting the front side surface portion 77 can be smoothly guided along the first circumferential surface portion 72. As a result, the generation of turbulent flow in the turning flow CF can be suppressed, and the rotation efficiency of the impeller 60 can be increased.

[0061] In this embodiment, the connection surface portion 76 is a curved surface curved in a concave shape. However, the connection surface portion 76 may be a convex curved surface that smoothly connects the first circumferential surface portion 72 and the front side surface portion 77 with a uniform radius of curvature. Further, the connection surface portion 76 may be a flat tapered surface that linearly connects the first circumferential surface portion 72 and the front side surface portion 77.

[0062] The rear side surface portion 78 faces the rear side in the rotational direction T. The front side surface portion 77 is a surface extending in the radial direction. The rear side surface portion 78 is located on the rear side in the rotational direction T from the second circumferential surface portion 73. The rear side surface portion 78 is connected to the second circumferential surface portion 73 via a corner portion.

[0063] As shown in FIG. 4, in the present embodiment, the plurality of guide portions 70 are arranged at intervals in the rotational direction. Similarly, the plurality of blade portions 63 are arranged at intervals in the rotational direction. Further, the number of guide portions 70 and the number of blade portions 63 are the same. Note that the intervals in the rotational direction of the plurality of guide portions 70 and the intervals in the rotational direction of the plurality of blade portions 63 may be the same or different. According to the present embodiment, by making the number of guide portions 70 and blade portions 63 the same and arranging each of the guide portions 70 and blade portions 63 at intervals from each other, variations in the weight balance in the rotational direction of the impeller 60 can be suppressed, and the rotational efficiency of the impeller 60 can be increased.

[0064] Also, according to the present embodiment, by making the number of guide portions 70 and blade portions 63 the same and arranging each of the guide portions 70 and blade portions 63 at intervals from each other, variations in the flow velocity of the air blown out from the air holes 61f of the guide portion 70 and sent radially outward by the blade portion 63 can be suppressed. For this reason, variations in the air resistance in the rotational direction of the impeller 60 can be suppressed, and the rotational efficiency of the impeller 60 can be increased.

[0065] Although the embodiments in the present disclosure have been described above, the present disclosure is not limited only to the configurations of the above-described embodiments, and the following configurations and methods can also be adopted.

[0066] In the above-described embodiment, the main plate, shroud, and plurality of blade portions of the impeller have been described as being separate members and fixed to each other. However, the main plate, shroud, and plurality of blade portions may be parts of a single member. Further, the main plate, shroud, and blade portions may each have a mode formed by combining a plurality of members.

[0067] In the above-described embodiment, the case where the centrifugal blower is adopted in a ceiling-embedded indoor unit has been described. However, the centrifugal blower of the embodiment can also be used in other types of indoor units, and can be widely used in various devices equipped with blowing means other than air conditioners. The heat exchanger shown in the above-described embodiment is merely an example of a pressure loss body placed in the air flow path generated by the centrifugal blower in the air conditioner. Therefore, for example, as a pressure loss body placed in the air flow path generated by the centrifugal blower in an air purifier, an air purification filter can be cited. That is, the centrifugal blower described in the above embodiment can also be adopted as a blower in the air purifier.

[0068] As described above, each configuration and each method described in this specification can be appropriately combined within a range that does not conflict with each other.

Description of Reference Numerals

[0069] 10... Indoor unit, 14... Indoor heat exchanger (heat exchanger), 40... Centrifugal blower, 50... Driving unit, 52... Rotating shaft, 60... Impeller, 61... Main plate, 61b... Hub, 61f... Air hole, 61fa... Opening, 62... Shroud, 63... Blade part, 70... Guide part, 70a... Outer peripheral surface, 72... First circumferential surface (circumferential surface), 73... Second circumferential surface (circumferential surface), 74... Third circumferential surface, 75... Canopy surface, 76... Connection surface, 77... Front side surface, D, d1, d2... Length, R... Axis of rotation, T... Direction of rotation

Claims

1. A drive unit having a rotating shaft that rotates about a rotation axis, An impeller disposed on one axial side of the rotation axis with respect to the drive unit and rotated by the drive unit in the forward direction of the rotation direction around the rotation axis, and comprising: The impeller includes: A main plate fixed to the rotating shaft, An annular shroud facing the main plate in the axial direction, A plurality of blade portions connecting the main plate and the shroud, The main plate has a hub that covers the drive unit from one axial side and the radially outer side of the rotation axis, The hub has a plurality of guide portions that project outward in the radial direction and are arranged in the rotation direction, Air holes that open outward in the radial direction are formed in the plurality of guide portions, The outer peripheral surfaces of the plurality of guide portions have a first circumferential surface portion that is located on the forward side of the rotation direction with respect to the air holes and faces the radially outer side, and a second circumferential surface portion that is located on the rearward side of the rotation direction with respect to the air holes and faces the radially outer side, The second circumferential surface portion extends in the rotation direction and is arranged continuously with the opening of the air hole in the rotation direction, The first circumferential surface portion and the second circumferential surface portion are each a curved surface that curves around the rotation axis, A centrifugal blower.

2. The first circumferential surface portion extends in the rotation direction and is arranged on the radially outer side of the opening of the air hole, The centrifugal blower according to claim 1.

3. The outer peripheral surface of the guide portion is A front side surface portion that is located on the forward side of the rotation direction with respect to the first circumferential surface portion and faces the forward side of the rotation direction, and A connection surface portion that connects the first circumferential surface portion and the front side surface portion, a portion extending radially from an edge on the front side in the rotational direction of the opening of the air hole to an end on the rear side in the rotational direction of the first circumferential surface; The connecting surface portion is inclined radially inward as it goes from the first circumferential surface toward the front side surface portion. The centrifugal blower according to claim 2.

4. The lengths in the rotational direction of the first circumferential surface and the second circumferential surface are each smaller than the length in the rotational direction of the air hole. The centrifugal blower according to any one of claims 1 to 3.

5. The outer peripheral surface of the guide portion has a third circumferential surface located on one axial side of the air hole and facing radially outward. The centrifugal blower according to any one of claims 1 to 4.

6. The outer peripheral surface of the guide portion has a third circumferential surface located on one axial side of the air hole and facing radially outward, and has a canopy surface portion located on one axial side of the air hole and facing one axial side, and the canopy surface portion is connected to the first circumferential surface, the second circumferential surface, and the third circumferential surface via a corner portion. The canopy surface portion is connected to the first circumferential surface, the second circumferential surface, and the third circumferential surface via a corner portion. The centrifugal blower according to any one of claims 1 to 4.

7. The plurality of guide portions are arranged at intervals from each other in the rotational direction. The plurality of blade portions are arranged at intervals from each other in the rotational direction. The number of the guide portions and the number of the blade portions are the same. The centrifugal blower according to any one of claims 1 to 6.

8. The centrifugal blower according to any one of claims 1 to 7, and a heat exchanger arranged around the centrifugal blower. An indoor unit.

Images