impeller

Abstract

Provided is an impeller in which stress concentration at a portion where a hub section and blade sections are densely packed can be reduced without providing a fillet at the bases of the blades. An impeller (23) comprises a hub section (33) disposed on a rotation center line C, a main plate section (31) projecting from the hub section (33) and extending radially on a plane orthogonal to the rotation center line, and a plurality of blade sections (32) projecting in one normal direction of the main plate section (31) so as to be arranged in an annular form, the plurality of blade sections (32) being open, and the outermost diameter (D2) drawn by the plurality of blade sections (32) being greater than the outermost diameter (D1) of the main plate section (31). The blade sections (32) are connected only to the main plate section (31), and each blade section has a leading edge (41) close to the rotation center line C, a trailing edge (42) far from the rotation center line C, and in a root section joined to the main plate section (31), a wing-side curved section (51) where the leading edge (41) curves away from the hub section (33) as the leading edge approaches the main plate section (31).

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to an impeller. [Background technology]

[0002] There is a known impeller that includes a disk body with a guide surface that guides fluid, such as air, flowing in from the direction of the rotation axis in the radial direction. The guide surface is provided with a plurality of blades arranged in the circumferential direction (direction of rotation). A boss portion that is attached to the rotation axis is provided at the center of the disk body.

[0003] The curvature of the leading edge root fillet of the blade is greater than the curvature of the side root fillets of the blade, which ensures sufficient flow passage between adjacent blades and reduces the concentration of stress acting on the blade root. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-185733 Summary of the Invention [Problem to be solved by the invention]

[0005] A typical impeller includes a hub portion fixed to a rotating shaft, a main plate portion connected to the hub portion and extending radially, and multiple blade portions protruding from the main plate portion. In conventional impellers, the hub portion is located inside the disk body corresponding to the main plate portion, and the multiple blade portions are located outside the disk body. Therefore, in conventional impellers, fillets provided at the base of each blade increase the thickness of the base of the blade without being obstructed by the hub portion, thereby reducing stress concentration at the base of the blade.

[0006] However, in the case of an impeller having a hub portion and a blade portion adjacent to the same surface of the main plate portion, the hub portion and the base of the blade are so close together that it may be difficult to ensure sufficient space to provide a fillet at the base of the blade.

[0007] Therefore, an object of the present invention is to provide an impeller that can reduce stress concentration in the area where the hub portion and the blade portions are closely spaced without providing a fillet at the base of the blade. [Means for solving the problem]

[0008] An impeller according to an embodiment of the present invention includes a hub portion disposed on a rotational centerline of the impeller, a main plate portion protruding from the hub portion and spreading radially on a plane perpendicular to the rotational centerline, and a plurality of blade portions protruding in one normal direction of the main plate portion and arranged in an annular shape, wherein the plurality of blade portions are open-type, and the outermost diameter of the plurality of blade portions is larger than the outermost diameter of the main plate portion, and each of the blade portions is connected only to the main plate portion and has an inner edge close to the rotational centerline and an outer edge far from the rotational centerline. At a root portion connected to the main plate portion, the inner edge curves so as to move away from the hub portion as it approaches the main plate portion, and the wing portion has a blade-side curved portion that intersects with a root end of the wing portion that contacts the main plate portion, and the main plate portion has, at a root portion connected to the hub portion, a main plate-side curved portion that is connected to the blade-side curved portion and curves so as to move away from the wing portion as it approaches the hub portion or curves in a concave shape that is opened toward the wing portion, and the blade-side curved portion and the main plate-side curved portion are connected at the root end of the wing portion. The point where the root end of the blade portion reaches the hub portion is defined as a dense point, and the main plate side curved portion is formed in the main plate portion between the dense point and a connecting point with the blade side curved portion. do. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view of an indoor unit of a refrigeration cycle apparatus including an impeller according to an embodiment of the present invention; [Figure 2] 1 is a schematic vertical cross-sectional view of an indoor unit of a refrigeration cycle device including an impeller according to an embodiment of the present invention; [Figure 3] FIG. 2 is a bottom view of the impeller according to the embodiment. [Figure 4]FIG. 2 is a perspective view showing the impeller according to the embodiment from the bottom side. [Figure 5] FIG. 2 is a vertical cross-sectional view of the impeller and bell mouth according to the embodiment. [Figure 6] FIG. 2 is a perspective view of the vicinity of the base of the blade of the impeller according to the embodiment. [Figure 7] FIG. 4 is a bottom view of the vicinity of the base of the blade of the impeller according to the embodiment. [Figure 8] FIG. 2 is a perspective view of a blade portion of the impeller according to the embodiment. [Figure 9] FIG. 2 is a perspective view of an impeller according to the embodiment. [Figure 10] FIG. 2 is a perspective view of an impeller according to the embodiment. [Figure 11] FIG. 10 is a perspective view showing another example of the impeller according to the embodiment from the bottom side. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of an impeller according to the present invention will be described with reference to Figures 1 to 11. Note that the same or corresponding components are denoted by the same reference numerals throughout the drawings.

[0011] FIG. 1 is a schematic perspective view of an indoor unit of a refrigeration cycle device including an impeller according to an embodiment of the present invention.

[0012] FIG. 2 is a schematic vertical cross-sectional view of an indoor unit of a refrigeration cycle device including an impeller according to an embodiment of the present invention.

[0013] The refrigeration cycle device according to this embodiment includes an indoor unit 1 installed indoors as a user side, and an outdoor unit (not shown) installed outdoors as a heat source side, as shown in FIG.

[0014] The refrigeration cycle device also includes a refrigeration cycle (not shown). The refrigeration cycle includes a heat exchanger (not shown) on the heat source side, a compressor (not shown), a heat exchanger 2 on the user side, an expander (not shown), and refrigerant piping (not shown) for circulating refrigerant through these devices. The refrigeration cycle may also include a four-way valve (not shown) for switching between cooling operation and heating operation of the refrigeration cycle device.

[0015] The indoor unit 1 houses the heat exchanger 2 on the user side of the refrigeration cycle. The outdoor unit houses the heat exchanger on the heat source side of the refrigeration cycle, a compressor, and a four-way valve. The expander may be housed in the indoor unit 1 or the outdoor unit. The outdoor unit and the indoor unit are connected via a crossover pipe (not shown). The crossover pipe is part of the refrigerant piping. The refrigeration cycle device conditions the air in the room by circulating refrigerant between the heat exchanger on the outdoor unit side and the heat exchanger 2 on the indoor unit 1 side.

[0016] The indoor unit 1 is installed inside a building and is installed by being embedded in the ceiling of the room or suspended from the ceiling or beams.

[0017] 1 and 2, an indoor unit 1 according to this embodiment includes a housing 5, a heat exchanger 2 provided within the housing 5, and a blower 6. The blower 6 includes an annular bellmouth 7 provided in the housing 5, and a turbofan 8 that draws air through the bellmouth 7 and blows the air toward the heat exchanger 2.

[0018] The indoor unit 1 also includes an electric expansion valve (not shown) which is an expander for the refrigeration cycle.

[0019] The housing 5 is a box-shaped body having a rectangular top, four rectangular side faces, and a rectangular bottom face. The top face of the housing 5 is closed by a top plate 11. A turbofan 8 is provided on the underside of the top plate 11. The four side faces of the housing 5 are closed by side plates 12. The corners between the side faces are beveled like chamfers. These chamfered portions are closed by inclined plates 13.

[0020] The bottom surface of the housing 5 is covered with a bottom plate 14. A circular intake port 16 is provided in the center of the bottom plate 14, which draws in air from below the indoor unit 1. A plurality of rectangular outlets 17 are provided on the outer edge of the bottom plate 14, which blow air downward. Each outlet 17 is aligned along one side of the rectangular bottom surface of the housing 5. Therefore, the indoor unit 1 draws in indoor air through the intake port 16 on the bottom surface of the housing 5, exchanges heat between the refrigerant and the air in the heat exchanger 2, and blows out the conditioned air from the outlets 17 on the bottom surface of the housing 5.

[0021] The heat exchanger 2 is fixed to the top plate 11 of the housing 5. In this embodiment, the heat exchanger 2 is, for example, a fin-and-tube type, and includes a large number of aligned aluminum alloy fins and refrigerant pipes that pass through the fins.

[0022] The heat exchanger 2 is provided inside the housing 5 and surrounds the radial outside of the turbofan 8. The inner peripheral surface of the heat exchanger 2 faces the turbofan 8, and the outer peripheral surface of the heat exchanger 2 faces the inner surface of the side plate 12. The heat exchanger 2 has flat plate portions 2a that face each side plate 12 of the housing 5, and curved plate portions 2b that curve facing the inclined plate 13 between two adjacent side plates 12 and connect the two adjacent flat plate portions 2a. There are four flat plate portions 2a and three curved plate portions 2b. In other words, the heat exchanger 2 is not a continuous ring.

[0023] An annular bellmouth 7 is provided at the suction port 16 of the bottom plate 14. The opening edge on the suction side of the bellmouth 7, i.e., the upstream end 7a of the bellmouth 7, is continuous with the outer surface 14a of the bottom plate 14. The opening edge on the blowing side of the bellmouth 7, i.e., the downstream end 7b of the bellmouth 7, is continuous with the inner surface 14b of the bottom plate 14. The inner surface 14b of the bottom plate 14 is flat, and reaches the heat exchanger 2 from the downstream end 7b of the bellmouth 7. The outer surface 14a of the bottom plate 14 is a flat upstream side surface 18 that is continuous with the upstream end 7a of the bellmouth 7, and the inner surface 14b of the bottom plate 14 is a flat downstream side surface 19 that is continuous with the downstream end 7b of the bellmouth 7.

[0024] A drain pan (not shown) may be provided below the heat exchanger 2 to collect condensation water that occurs on the surface of the heat exchanger 2. During cooling operation in which the heat exchanger 2 functions as an evaporator, moisture contained in the air passing through the heat exchanger 2, i.e., indoor humidity, condenses on the surface of the heat exchanger 2, adheres to the heat exchanger 2 as condensation water, and drips from the heat exchanger 2. The drain pan collects the condensation water that drops from the heat exchanger 2. The condensation water that accumulates in the drain pan is pumped by a drain pump (not shown) provided in the housing 5, and is drained to the outside of the indoor unit 1 through a drain pipe (not shown).

[0025] The drain pan preferably has a recess for receiving condensed water in a flat portion that extends from the downstream end 7b of the bell mouth 7 toward the heat exchanger 2, at a location as close as possible to the heat exchanger 2. The drain pan is preferably formed from a heat insulating material that is integrated into the bottom plate 14 of the housing 5.

[0026] The turbofan 8 is provided with a fan motor 22 having a rotary shaft 21 extending in the vertical direction at approximately the center of the housing 5, and an impeller 23 fixed to the rotary shaft 21 so as to rotate integrally with the rotary shaft 21.

[0027] The fan motor 22 rotates the impeller 23. The fan motor 22 is fixed to the inner surface of the top plate 11 of the housing 5 via a fixture 25.

[0028] The rotating impeller 23 draws in air around the housing 5 through the bell mouth 7 of the intake port 16, and blows the air radially in a direction along the inner surface 14b of the bottom plate 14, and then blows the blown air onto the heat exchanger 2.

[0029] In a plan view, the center of the annular heat exchanger 2, the center of rotation of the turbofan 8, the center of the circular air inlet 16, and the center of the annular bell mouth 7 are substantially aligned. The maximum outer diameter A of the turbofan 8 is larger than the opening diameter B of the bell mouth 7.

[0030] A rotation center line C of the impeller 23 coincides with the center line of the rotation shaft 21 of the fan motor 22, and extends vertically when the indoor unit 1 is installed.

[0031] When the air conditioner is operating in cooling mode, the compressor in the outdoor unit discharges high-temperature, high-pressure gas refrigerant and sends it to the outdoor heat exchanger (condenser). The outdoor heat exchanger exchanges heat between the refrigerant flowing inside it and the outdoor air, condensing the refrigerant. The condensed liquid refrigerant is sent to the indoor unit 1 through the refrigerant piping. The indoor unit 1 expands the liquid refrigerant flowing in from the refrigerant piping using an electric expansion valve, and sends the low-temperature gas-liquid mixed refrigerant to the heat exchanger 2 (evaporator). The heat exchanger 2 exchanges heat between the low-temperature refrigerant flowing inside it and the indoor air, gasifying the refrigerant. During this process, the room is cooled by the low-temperature air blown out from the indoor unit 1.

[0032] When the air conditioner is in heating operation, the compressor in the outdoor unit discharges high-temperature, high-pressure gas refrigerant and sends it to the heat exchanger 2 (condenser) in the indoor unit 1. The heat exchanger 2 exchanges heat between the refrigerant flowing inside and the indoor air, causing the refrigerant to condense. At this time, the room is heated by the high-temperature air blown out from the indoor unit 1. Next, the impeller 23 will be described in detail.

[0033] FIG. 3 is a bottom view of the impeller according to this embodiment.

[0034] FIG. 4 is a perspective view showing the impeller according to this embodiment from the bottom side.

[0035] FIG. 5 is a vertical cross-sectional view of the impeller and bell mouth according to this embodiment.

[0036] As shown in Figures 3 to 5 in addition to Figures 1 and 2, the impeller 23 of this embodiment comprises a main plate portion 31 that is substantially parallel to the downstream side surface 19 that is connected to the bell mouth 7 and that extends radially, a plurality of blade portions 32 that are arranged in a ring shape and protrude from the main plate portion 31 toward the downstream side surface 19 and the bell mouth 7, and a hub portion 33 that is provided in the center of the main plate portion 31.

[0037] The impeller 23 is an integrally molded product made of fiber reinforced plastics (FRP), aluminum alloy, or magnesium metal. The impeller 23 is made of, for example, fiber reinforced plastic, and is integrally molded by hand layup.

[0038] The main plate portion 31 is a flat plate having a substantially uniform thickness. The main plate portion 31 is a collection of a plurality of petals 35 that extend radially outward from the hub portion 33 in the radial direction of the impeller 23.

[0039] Each petal 35 has a first side 35a with a straight edge and a second side 35b with a straight edge, and extends in a triangular or tapered shape from the center (toward the hub 33). The first side 35a of each petal 35 is also called the first edge of the main plate 31, and the second side 35b of each petal 35 is also called the second edge of the main plate 31.

[0040] In a pair of adjacent petals 35, the first side 35a of one petal 35 faces the second side 35b of the other petal 35. In other words, the first side 35a of one petal 35 and the second side 35b of the other petal 35 are separated by a gap in the circumferential direction of the main plate 31 and face each other in the circumferential direction.

[0041] All of the petals 35 have substantially the same shape. The ends of the petals 35 located radially inward of the turbofan 8, i.e., the root ends of the petals 35, closely surround the outer periphery of the hub portion 33. In other words, for a pair of adjacent petals 35, the root end of the first side 35a of one petal 35 coincides with the root end of the second side 35b of the other petal 35. The ends of the petals 35 located radially outward of the turbofan 8, i.e., the protruding ends of the petals 35, can be connected by an imaginary circle, and the diameter of this imaginary circle corresponds to the outermost diameter D1 of the main plate portion 31. The protruding ends of the petals 35 are the corners formed by the first side 35a and the second side 35b.

[0042] The multiple wings 32 and the hub 33 protrude in the same direction from the main plate 31. The hub 33 has a truncated cone shape that narrows as it moves away from the main plate 31. The protruding height of the multiple wings 32 relative to the main plate 31 is greater than the protruding height of the hub 33.

[0043] The number of the wings 32, that is, the number of wings 32, is a prime number, and is 11 in this embodiment.

[0044] All of the blade portions 32 have substantially the same shape. The blade portions 32 are open-type. That is, the impeller 23 does not have an element that connects the blade portions 32 in the circumferential direction, such as a shroud that connects the protruding ends 32a of the blade portions 32. Each blade portion 32 is connected only to the main plate portion 31 and is not in contact with or connected to the hub portion 33.

[0045] Root end 32b of each wing portion 32 is the edge of each wing portion 32 that is connected to main plate portion 31. Root end 32b of each wing portion 32 is connected to first side portion 35a of each petal portion 35. In other words, each wing portion 32 protrudes from first side portion 35a of each petal portion 35. Therefore, root end 32b of each wing portion 32 has the same linear shape as first side portion 35a of each petal portion 35, and also has a linear shape that coincides with the wing chord.

[0046] Each of the blade portions 32 is inclined in the circumferential direction of the turbofan 8 and in a direction away from the second side portion 35b of each of the petals 35. Furthermore, each of the blade portions 32 is inclined radially outward from the root end 32b toward the protruding end 32a of the turbofan 8. Therefore, in the state shown in FIG. 3 when the impeller 23 is viewed along the rotation center line C, the outermost diameter D2 of the multiple blade portions 32 is greater than the outermost diameter D1 of the main plate portion 31.

[0047] The impeller 23 rotates in a direction R in which the first side 35a of each petal 35 precedes the second side 35b, causing the air to flow. That is, the leading edge 41 of each wing 32 is located on the inner circumferential side of the impeller 23, and the trailing edge 42 of each wing 32 is located on the outer circumferential side of the impeller 23. In other words, the leading edge 41 of each wing 32 is an inner edge that is relatively close to the rotation center line C of the impeller 23, and the trailing edge 42 of each wing 32 is an outer edge that is relatively far from the rotation center line C of the impeller 23.

[0048] When viewed from the direction along the rotation center line of the impeller 23 (FIG. 3), the angle θ formed by a first line segment L1 connecting the trailing edge 42 of the first blade portion 32, which is one of the circumferentially adjacent blade portions, to the rotation center line C, and a second line segment L2 connecting the trailing edge 42 of the second blade portion 32, which is the other blade portion, to the rotation center line C, is preferably 25 degrees or greater. In other words, the number of blade portions 32 is preferably a prime number of 13 or less, and is 11 in this embodiment.

[0049] The protruding end 32a of each blade portion 32 has a first portion 45 located close to the downstream side surface 19 and a second portion 46 that protrudes further toward the upstream end 7a of the bell mouth 7 than the downstream end 7b of the bell mouth 7. In other words, the protruding end 32a of each blade portion 32 has a convex portion 47 that fits inside the bell mouth 7. The convex portion 47 protrudes in accordance with the shape of the bell mouth 7. The second portion 46 is the ridge line of the convex portion 47. In this embodiment, the first portion 45 and the downstream side surface 19 of the blade portion 32 are arranged to face each other with a gap of about several millimeters between them. It is preferable that the gap between the impeller 23 and the bell mouth 7 be as close as possible within a range that allows the impeller 23 to rotate smoothly without interfering with the bell mouth 7.

[0050] The thickness of each of the wing portions 32 is thinner than the thickness of the main plate portion 31. Such a thickness relationship reduces the centrifugal force acting on the wing portions 32 compared to when the thickness of each of the wing portions 32 is the same as that of the main plate portion 31 or when the thickness of each of the wing portions 32 is thicker than that of the main plate portion 31. The reduction in centrifugal force reduces deformation of the wing portions 32 and prevents a decrease in air volume due to deformation of the wing portions 32. Furthermore, the main plate portion 31, which is thicker than each of the wing portions 32, reduces deformation of the wing portions 32 due to centrifugal force and prevents a decrease in air volume due to deformation of the wing portions 32.

[0051] FIG. 6 is a perspective view of the vicinity of the base of the blade of the impeller according to this embodiment.

[0052] FIG. 7 is a bottom view of the vicinity of the base of the blade of the impeller according to this embodiment.

[0053] 6 and 7, the impeller 23 according to this embodiment has a blade-side curved portion 51 at the base portion of the blade portion 32 connected to the main plate portion 31, the blade-side curved portion 51 being curved such that the leading edge 41 moves away from the hub portion 33 as it approaches the main plate portion 31. The blade-side curved portion 51 eliminates the corner formed by the leading edge 41 of the blade portion 32 and the base end 32b of the blade portion 32. In this embodiment, the blade-side curved portion 51 is formed as a notch by removing a part of the base side of the blade portion 32, including this corner.

[0054] Furthermore, the impeller 23 has a main plate-side curved portion 52 at a root portion of the main plate 31 that connects to the hub portion 33. The main plate-side curved portion 52 connects to the blade-side curved portion 51 and curves so as to move away from the nearest blade portion 32 as it approaches the hub portion 33. The main plate-side curved portion 52 eliminates the corner formed by the root end of the hub portion 33 and the root end 32b of the blade portion 32. In this embodiment, the main plate-side curved portion 52, like the blade-side curved portion 51, is formed as a notch by removing a part of the root side of the petal portion 35, including this corner.

[0055] Note that the root ends 32b of the wing portions 32 and the first sides 35a of the petal portions 35 substantially coincide with each other. Therefore, in other words for the blade-side curved portion 51 and the main plate-side curved portion 52, the blade-side curved portion 51 eliminates a corner formed between the leading edge 41 of the wing portion 32 and the first sides 35a of the petal portions 35 at the root portions of the wing portions 32. Furthermore, the main plate-side curved portion 52 eliminates a corner formed between the first sides 35a of the petal portions 35 and the root ends of the hub portion 33 at the root portions of the petal portions 35.

[0056] In addition, the main plate side curved portion 52 may be provided at the root portion connected to the hub portion 33 of the main plate portion 31, connected to the blade side curved portion 51, and curved in a concave shape that opens toward the blade portion 32.

[0057] Here, the line segment that is an extension of root end 32b of wing section 32 and first side portion 35a of petal section 35 and reaches the root end of hub section 33 is called wing tip extension line EL1, and the line segment that is an extension of leading edge 41 of wing section 32 and reaches the root end of hub section 33 is called wing leading edge extension line EL2. These wing tip extension line EL1 and wing leading edge extension line EL2 essentially intersect and converge at the root end of hub section 33. The point where the root end of hub section 33, wing tip extension line EL1, and wing leading edge extension line EL2 essentially converge is called convergence point 53.

[0058] The dense point 53 may extend over a circular range with a diameter of about 5 mm, taking into consideration the manufacturability of the impeller 23. In other words, at the dense point 53, the root end of the hub portion 33, the blade tip extension line EL1, and the blade leading edge extension line EL2 may be gathered within a circular range of 0.5 to 2.0 percent of the outermost diameter of the impeller 23.

[0059] As a comparative example, an impeller without the blade-side curved portion 51 and the main-plate-side curved portion 52 is assumed. In this case, the hub portion 33, the petals 35 of the main plate portion 31, and the blades 32 are adjacent to each other at the dense point 53. That is, the root end of the hub portion 33, the first side 35a of the petals 35, the second side 35b of the adjacent petals 35, the root end 32b of the blades 32, and the leading edge 41 of the blades 32 essentially intersect at the dense point 53. The force acting on the blades 32 due to the rotation of the impeller 23 is supported by the main plate portion 31 and the hub portion 33. Therefore, stress acting on the impeller 23 is concentrated at the dense point 53. If the stress at the dense point 53 becomes excessive, there is a risk that at least one of the areas of the hub portion 33 close to the dense point 53, the areas of the petal portion 35 close to the dense point 53, and the areas of the wing portion 32 close to the dense point 53 may be damaged.

[0060] Therefore, the blade-side curved portion 51 and the main plate-side curved portion 52 prevent the hub portion 33, the petal portions 35 of the main plate portion 31, and the blade portions 32 from concentrating at the dense point 53. In other words, in the impeller 23 according to this embodiment, the hub portion 33, the petal portions 35 of the main plate portion 31, and the blade portions 32 are not adjacent to each other at the dense point 53.

[0061] The blade-side curved portion 51 and the main-plate-side curved portion 52 have a concave shape recessed in a direction away from the dense point 53. Therefore, the blade-side curved portion 51 and the main-plate-side curved portion 52 slightly reduce the blade area while reliably reducing the stress concentrating at the dense point 53, that is, the corner where the hub portion 33, the petal portions 35 of the main plate portion 31, and the wing portions 32 come into contact with each other. Specifically, the blade-side curved portion 51 reliably reduces the stress concentrating on the root portion of the wing portion 32 on the leading edge 41 side, and the main-plate-side curved portion 52 reliably reduces the stress concentrating on the root portion of the main plate portion 31 on the first side 35a side.

[0062] Furthermore, it is difficult to provide thick portions for providing fillets as in conventional impellers. Even if the thicknesses of the hub portion 33, main plate portion 31, and blade portions 32 are increased, it is unavoidable that the hub portion 33, main plate portion 31, and blade portions 32 are adjacent to each other at the dense points 53. Therefore, even if the thicknesses of the hub portion 33, main plate portion 31, and blade portions 32 are increased, it is not possible to ensure thick portions for providing fillets. However, the blade-side curved portion 51 and the main plate-side curved portion 52 can easily prevent the hub portion 33, main plate portion 31, and blade portions 32 from concentrating at the dense points 53.

[0063] The blade side curved portion 51 and the main plate side curved portion 52 may be formed during the molding or forming process of the impeller 23, or may be formed by removing parts of the main plate portion 31 and the blade portion 32 by machining after the impeller 23 has been molded or formed.

[0064] The impeller 23 may include only the blade-side curved portion 51. Even in this case, the hub portion 33, the petal portions 35 of the main plate portion 31, and the blade portions 32 can be prevented from being adjacent to each other at the crowded points 53. Note that the angle θ1 formed by the blade-side curved portion 51 and the main plate-side curved portion 52 is greater than the angle θ2 formed by the blade-side curved portion 51 and the first side portion 35a of the main plate portion 31. Therefore, providing both the blade-side curved portion 51 and the main plate-side curved portion 52 reliably reduces the stress concentrated at the base portions of the blade portions 32 and the main plate portion 31.

[0065] FIG. 8 is a perspective view of a blade portion of the impeller according to this embodiment.

[0066] As shown in FIG. 8 , the planar shape of the blade portion 32 of the impeller 23 according to this embodiment is close to a rectangle, e.g., a parallelogram. The root end 32b has a linear shape that connects to the first side 35a of the petal portion 35. The line connecting points a and b in FIG. 8 is the root end 32b. Here, point a is the proximal end of the leading edge 41 and corresponds to the dense point 53. Point b is the proximal end of the trailing edge 42. The protruding end 32a is non-linear and has a convex portion 47 that protrudes in a direction away from the root end 32b beyond an imaginary line VL that passes through the protruding end of the trailing edge 42 and is parallel to the root end 32b. The protruding end 32a is the line connecting points c, d, and e in FIG. 8. Here, point c is the distal end of the leading edge 41, and point e is the distal end of the trailing edge 42.

[0067] The line connecting points a and c in FIG. 8 is the leading edge 41 of the wing portion 32, and the line connecting points b and e in FIG.

[0068] The protruding portion 47 has a straight edge 48 that is continuous with the leading edge 41 and is parallel to the root end 32b and the main plate portion 31, and a curved edge 49 that connects the straight edge 48 and the trailing edge 42. The straight edge 48 is a straight line connecting points c and d in FIG. 8, and the curved edge 49 is a curve connecting points d and e in FIG. 8. The straight edge 48 and a portion of the curved edge 49 that follows the bell mouth 7 form the second portion 46 of the protruding end 32a, and the remainder of the curved edge 49 forms the first portion 45 located close to the downstream side surface 19. In other words, the remainder of the curved edge 49 is substantially parallel to the root end 32b. There are gaps between the protruding end 32a and the bell mouth 7, and between the protruding end 32a and the downstream side surface 19, sufficient to not impede the rotation of the impeller 23. These gaps are preferably 5 millimeters or less.

[0069] 9 and 10 are perspective views of the impeller according to this embodiment.

[0070] As shown in FIG. 9, the impeller 23 according to this embodiment is a one-piece molded product or a one-piece molded product made of a composite material having a fiber material 55 oriented so as to straddle the hub portion 33 and the main plate portion 31.

[0071] As shown in FIG. 10, the impeller 23 according to this embodiment is a one-piece molded product or a one-piece molded product made of a composite material having a fiber material 55 oriented so as to straddle the main plate portion 31 and each of the blade portions 32.

[0072] The impeller 23 is formed by laminating sheet-like prepregs, such as a UD material in which carbon fibers are unidirectional prepregs, or a cross material in which warp and weft threads are woven. In this case, the impeller 23 is molded by a method such as autoclave molding, in which resin is cured in a high-temperature, high-pressure vessel, RTM (Resin Transfer Molding), in which a carbon fiber substrate is placed in a mold and then resin is injected and cured, or press molding, in which prepregs are placed in a preheated mold and cured while being pressed with a press.

[0073] The impeller 23 may also be made of a resin composite material containing plant fibers, which is molded by injection molding, extrusion molding, etc. The plant fibers are oriented by the flow of resin during molding.

[0074] The impeller 23 may include fiber material 55 oriented in any direction other than the fiber material 55 oriented as shown in Figures 9 and 10. For example, the impeller 23 may include fiber material 55 oriented perpendicular to the fiber material 55 shown in Figures 9 and 10.

[0075] FIG. 11 is a perspective view showing another example of the impeller according to this embodiment from the bottom side.

[0076] 11, the impeller 23A according to this embodiment may include a reinforcing member 58 that connects each blade portion 32 to the hub portion 33. Unlike the shrouds of conventional impellers, which have a width in the radial direction and have a substantial difference in size between the outer diameter and the inner diameter, the reinforcing member 58 is a linear member, such as a steel wire.

[0077] The reinforcing members 58 extend from the hub portion 33 to the protruding ends 32a or leading edges 41 of the respective blade portions 32, like the ribs of an umbrella. The reinforcing members 58 prevent the respective blade portions 32 from collapsing radially outward of the impeller 23A due to rotation of the impeller 23A, and reduce stress concentration at the dense points 53.

[0078] As described above, the impellers 23, 23A according to the present embodiment do not have a shroud and can be integrally molded. Therefore, the impellers 23, 23A eliminate causes of defects, such as poor welding and poor adhesion, that occur when a separate shroud is joined to the blade portion, and can reduce the amount of imbalance in rotation compared to when a separate shroud is joined to the blade portion 32.

[0079] Furthermore, the impellers 23, 23A according to this embodiment include a plurality of blades 32 connected only to the main plate 31. Therefore, the impellers 23, 23A can be easily made lighter than conventional impellers that have a shroud or frame, and can also eliminate obstructions to the air flow.

[0080] Furthermore, impellers 23, 23A according to this embodiment include blades 32 having root ends 32b that are continuous with first sides 35a of respective petals 35, which are part of the edge of main plate 31. Therefore, impellers 23, 23A can smoothly blow out the airflow that has been given energy by blades 32.

[0081] Furthermore, impellers 23, 23A according to this embodiment have first side portions 35a and second side portions 35b of petal portions 35 that face each other across a gap in the circumferential direction of main plate portion 31. Therefore, impellers 23, 23A can blow air that has been given energy by blade portions 32 through the gaps between adjacent petals 35. This air flow improves the air-blowing function of impeller 23. Furthermore, the gaps between adjacent petals 35 improve the workability of each process when integrally molding impellers 23, 23A, and facilitate demolding.

[0082] Furthermore, the impellers 23, 23A according to this embodiment include a plurality of blades 32 that protrude higher than the protruding height of the hub portion 33. Therefore, the impeller 23 can reduce the airflow resistance of the hub portion 33 and easily push out the airflow with the blades 32.

[0083] Furthermore, the thickness of each of the blade portions 32 of the impellers 23, 23A according to this embodiment is thinner than the thickness of the main plate portion 31. Therefore, the impellers 23, 23A reduce deformation of the blade portions 32 and prevent a decrease in air volume due to deformation of the blade portions 32.

[0084] Impellers 23, 23A according to this embodiment have blade-side curved portions 51 at the base of each blade portion 32, which curve such that leading edges 41 move away from hub portion 33 the closer they are to main plate 31. Therefore, impellers 23, 23A do not have corners formed by leading edges 41 of blade portions 32 and first sides 35a of petal portions 35, and stress concentration on the leading edge 41 side at the base of each blade portion 32 is reliably reduced.

[0085] Furthermore, impellers 23, 23A according to the present embodiment have, at the base of main plate 31, main plate-side curved portion 52 that is connected to blade-side curved portion 51 and curves so as to move away from the nearest blade portion 32 as it approaches hub 33. Therefore, impellers 23, 23A do not have a corner formed by the base end of hub 33 and first side 35a of petal 35, and the stress concentrated on the first side 35a side at the base of main plate 31 is reliably reduced.

[0086] Furthermore, the impeller 23A according to this embodiment includes a reinforcing member 58 that connects the blade portions 32 and the hub portion 33. Therefore, even without a shroud, the impeller 23A reduces the weight of the entire impeller 23, reduces the effect of centrifugal force on the blade portions 32, suppresses a decrease in air volume, and prevents collisions between the bell mouth 7 and the blade portions 32 due to deformation of the blade portions 32. Furthermore, the impeller 23A prevents each blade portion 32 from collapsing radially outward due to rotation of the impeller 23A, and can reliably reduce stress concentrated at the base of each blade portion 32 and the base of the main plate portion 31.

[0087] Furthermore, impellers 23, 23A according to the present embodiment are integrally molded or one-piece molded products made of a composite material having fiber material 55 oriented so as to straddle hub portion 33 and main plate portion 31. Therefore, even if the boundary between hub portion 33 and main plate portion 31 is damaged, impellers 23, 23A can prevent main plate portion 31 and blade portions 32 from easily flying apart.

[0088] Furthermore, the impellers 23, 23A according to this embodiment are integrally molded or one-piece molded products made of a composite material having fiber material 55 oriented so as to straddle the main plate portion 31 and each of the blade portions 32. Therefore, even if the boundary portion between the main plate portion 31 and the blade portions 32 of the impellers 23, 23A is damaged, the blade portions 32 can be prevented from easily scattering.

[0089] Therefore, according to the impellers 23, 23A according to this embodiment, it is possible to reduce the concentration of stress at the area where the hub portion 33 and the blade portions 32 are closely spaced without providing a fillet at the base of the blade portions 32.

[0090] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0091] 1...indoor unit, 2...heat exchanger, 2a...flat plate portion, 2b...curved plate portion, 5...casing, 6...blower device, 7...bell mouth, 7a...upstream end, 7b...downstream end, 8...turbo fan, 11...top plate, 12...side plate, 13...inclined plate, 14...bottom plate, 14a...outer surface, 14b...inner surface, 16...intake port, 17...air outlet, 18...upstream side surface, 19...downstream side surface, 21...rotating shaft, 22...fan motor, 23 , 23A...impeller, 25...fixing device, 31...main plate portion, 32...wing portion, 32a...protruding end, 32b...root end, 33...hub portion, 35...petal portion, 35a...first side portion, 35b...second side portion, 41...leading edge, 42...trailing edge, 45...first portion, 46...second portion, 47...convex portion, 48...straight edge, 49...curved edge, 51...blade side curved portion, 52...main plate side curved portion, 53...dense point, 55...fibrous material, 58...reinforcing member.

Claims

1. a hub portion disposed on the rotation center line of the impeller; a main plate portion that protrudes from the hub portion and spreads radially on a plane perpendicular to the rotation center line; a plurality of wing portions arranged in an annular shape and projecting in one normal direction of the main plate portion, the plurality of wings are open-type; an outermost diameter of the plurality of wing portions is larger than an outermost diameter of the main plate portion; Each of the wings comprises: an inner edge connected only to the main plate portion and close to the rotation center line, and an outer edge far from the rotation center line, At a root portion connected to the main plate portion, the inner edge curves so as to move away from the hub portion as it approaches the main plate portion, and the blade portion has a blade-side curved portion that intersects with a root end of the blade portion that contacts the main plate portion, the main plate portion has, at a root portion connected to the hub portion, a main plate-side curved portion that is connected to the blade-side curved portion and that curves away from the airfoil portion as it approaches the hub portion or curves in a concave shape that is opened toward the airfoil portion, the blade-side curved portion and the main-plate-side curved portion are connected to each other at a root end of the blade portion, a point where the root ends of the blade portions reach the hub portion is defined as a dense point, and the main plate-side curved portion is formed in the main plate portion between the dense point and a connecting point with the blade-side curved portion.

2. a hub portion disposed on the rotation center line of the impeller; a main plate portion having a plurality of petals formed along a plane perpendicular to the rotational centerline and extending radially outward from the hub portion; A plurality of wing portions extending from each of the plurality of petal portions in a normal direction of one of the main plate portions and arranged in a circumferential direction with respect to the rotation center line, Each of the petals has a first side portion that forms one end in the circumferential direction and a second side portion that forms the other end, the plurality of wings are open-type; When the plurality of wing portions are viewed along the rotation center line, the outermost diameter of the plurality of wing portions is larger than the outermost diameter of the main plate portion, Each of the wings comprises: an inner edge extending from the first side portion of the petal portion and connected to the main plate portion, and separated from the hub portion via a gap in the radial direction; an inner edge extending from an inner diameter side of the first side portion and close to the rotation center line; and an outer edge extending from an outer diameter side of the first side portion and far from the rotation center line; At a base portion connected to the petal portion, the inner edge curves so as to move away from the hub portion as it approaches the petal portion, and the wing portion has a blade-side curved portion that intersects with a base end of the wing portion that contacts the petal portion, the main plate portion has a main plate-side curved portion that is connected to the vane-side curved portion at the base of each of the petals that is connected to the hub portion, and that curves away from the wing portion as it approaches the hub portion, or curves in a concave shape that is opened toward the wing portion, the blade-side curved portion and the main-plate-side curved portion are connected to each other at a root end of the blade portion, a point where the root end of the blade portion reaches the hub portion is defined as a dense point, and the main plate-side curved portion is formed in the petal portion between the dense point and a connecting point with the blade-side curved portion.

3. The impeller according to claim 2 , wherein the inner edge is provided forward of the outer edge in the rotation direction of the impeller.

4. 4. The impeller according to claim 3, wherein the inner edge and the outer edge each have a proximal end close to the petals and a distal end far from the petals, and the distal end of the inner edge is located radially inward of the distal end of the outer edge.

5. The impeller according to claim 1 , further comprising a reinforcing member that connects each of the plurality of blade portions to the hub portion.

6. The impeller according to claim 1 , wherein the impeller is a single-piece molded product or a single-piece formed product made of a composite material having a fiber material oriented so as to straddle the hub portion and the main plate portion.

7. The impeller according to claim 1 , wherein the impeller is a single-piece molded product or a single-piece molded product made of a composite material having a fiber material oriented so as to straddle the main plate portion and each of the blade portions.

Images