Axial flow fan, air blower, and air conditioner

Abstract

This axial flow fan is provided with a hub that is rotationally driven and forms a rotational axis, and a blade that is formed around the hub and comprises a leading edge part, a trailing edge part, an inner edge part which is a portion connected to the hub, and an outer edge part forming an outer edge between the leading edge part and the trailing edge part. The blade comprises: a reduced part that forms, in a leading edge part-side portion of the portion forming the outer edge part, a portion in which the outer diameter of the blade is reduced compared to a trailing edge part-side portion forming the maximum diameter of the blade; and an outer peripheral part that forms, in the reduced part, a pressure side that curves from the downstream side to the upstream side in a direction in which a fluid that flows during rotation of the blade flows, as the pressure side extends from the inner edge part-side portion toward the outer edge part. The outer peripheral part is formed so that the width thereof in a radial direction about the rotational axis is greater in the trailing edge part-side portion than in the leading edge part–side portion.

Description

Axial flow fan, blower, and air conditioner

[0001] The present disclosure relates to an axial fan having a plurality of blades, a blower including the axial fan, and an air conditioner including the blower.

[0002] Conventionally, axial fans have been proposed that have a hub serving as the center of rotation and multiple blades attached to the outer periphery of the hub (see, for example, Patent Document 1). The axial fan of Patent Document 1 has a bent portion on the outer periphery of each blade that is bent upward toward the suction side, and the radial width of the bent portion is gradually increased from the leading edge to the trailing edge. This configuration of the axial fan of Patent Document 1 smoothly guides a blade tip vortex from the leading edge to the trailing edge, and also makes it difficult for the generated blade tip vortex to separate from the suction surface.

[0003] Patent No. 3979388

[0004] When there is no structure upstream of the axial fan or when the fan is separated from a structure, airflow with little turbulence flows toward the blades, resulting in small tip vortices occurring at the leading edges of the blades. However, when a structure such as a motor support is present upstream of the axial fan, the airflow behind the structure is turbulent. When turbulent airflow flows into the leading edges of the outer periphery of the blades, the axial fan is affected by the peripheral speed of the outermost periphery of the fan, causing large airflow leakage at the leading edges of the blades, increasing the formation of tip vortices. When a structure such as a motor support is present upstream of the axial fan, the small curvature at the bent portions on the leading edges of the blades in the axial fan of Patent Document 1 does not stabilize the tip vortex, which may reduce the efficiency of the axial fan.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a highly efficient axial flow fan, blower, and air conditioner in which blade tip vortices are stabilized even when turbulent airflow flows toward the blades.

[0006] The axial flow fan of the present disclosure comprises a hub that is driven to rotate and forms a rotation axis, and a blade formed around the hub and having a leading edge, a trailing edge, an inner edge that connects to the hub, and an outer edge that forms the outer edge between the leading edge and the trailing edge, and the blade has a reduced section in the leading edge side of the part that forms the outer edge where the outer diameter of the blade is reduced compared to the trailing edge side that forms the maximum diameter of the blade, and an outer peripheral section in the reduced section that forms a positive pressure surface that curves from the downstream side to the upstream side in the flow direction of the fluid that flows when the blade rotates as it moves from the inner edge side part to the outer edge, and the outer peripheral section is formed so that the radial width of the outer peripheral section, centered on the rotation axis, is greater in the trailing edge side part than in the leading edge side part.

[0007] A blower according to the present disclosure includes an axial fan having the above-described configuration and a drive source that applies a driving force to the axial fan.

[0008] The air conditioner of the present disclosure comprises a blower of the above-described configuration, a motor support that supports a drive source, a condenser that condenses the refrigerant, and an evaporator that evaporates the refrigerant, and the blower blows air to at least one of the condenser and the evaporator.

[0009] According to the present disclosure, an axial flow fan has a blade with a reduced diameter at the leading edge side by including a converging portion. The leading edge portion is closer to the rotation axis than the outermost portion of the blade, resulting in a lower circumferential velocity at the leading edge side of the blade. Therefore, even if a turbulent fluid flow enters the axial flow fan due to a structure such as a motor support, the low peripheral velocity at the leading edge side of the blade reduces the tip vortex formed at the leading edge side of the blade. Furthermore, the axial flow fan has an outer peripheral portion at the converging portion that forms a pressure surface that curves from downstream to upstream as it moves from the inner peripheral portion toward the outer edge. This outer peripheral portion is formed so that its radial width about the rotation axis is larger at the trailing edge side than at the leading edge side. The axial flow fan has an outer peripheral portion with this configuration, allowing the tip vortex, which expands from the leading edge side toward the trailing edge side, to follow the outer peripheral portion. Therefore, the tip vortex on the suction surface of the axial flow fan is stable and undisturbed, improving fan efficiency and achieving high efficiency.

[0010] 14 is a front view showing a schematic configuration of an axial fan according to embodiment 1. FIG. 15 is a front view of a blade in the axial fan according to embodiment 1. FIG. 16 is a cross-sectional view of a blade in the axial fan according to embodiment 1. FIG. 17 is a front view of a first modified example of a blade in the axial fan according to embodiment 1. FIG. 18 is a front view of a second modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a front view of a third modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a front view of a fourth modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a front view of a fifth modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a front view of a sixth modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a front view of a seventh modified example of a blade in the axial fan according to embodiment 1. FIG. 19 is a conceptual diagram of a radial cross section of an axial fan according to a comparative example. FIG. 19 is a perspective view of an axial fan according to a second comparative example. FIG. 19 is a side view of the axial fan according to the second comparative example. FIG. 19 is a conceptual diagram of an outdoor unit used in an air conditioner equipped with the axial fan according to the second comparative example. FIG. 19 is a conceptual diagram showing the relationship between a motor support and an axial fan in an outdoor unit used in the air conditioner shown in the comparative example of FIG. 10 is a front view of a blade in an axial fan according to embodiment 2. FIG. 11 is a cross-sectional view of a blade in an axial fan according to embodiment 2. FIG. 12 is a front view of a first modified example of a blade in an axial fan according to embodiment 2. FIG. 13 is a cross-sectional view of a blade in an axial fan according to embodiment 2. FIG. 14 is a front view of a first modified example of a blade in an axial fan according to embodiment 2. FIG. 15 is a front view of a third modified example of a blade in an axial fan according to embodiment 2. FIG. 16 is a front view of a fourth modified example of a blade in an axial fan according to embodiment 2. FIG. 17 is a front view of a fifth modified example of a blade in an axial fan according to embodiment 2. FIG. 18 is a front view of a blade in an axial fan according to embodiment 3. FIG. 19 is a cross-sectional view of a blade in an axial fan according to embodiment 3. FIG. 19 is a cross-sectional view of a blade in an axial fan according to embodiment 4. FIG. 19 is a cross-sectional view of a blade in an axial fan according to embodiment 5. FIG. 19 is a cross-sectional view of a first modified example of a blade in an axial fan according to embodiment 5. FIG. 19 is a cross-sectional view of a blade in an axial fan according to embodiment 6. FIG. 19 is a schematic diagram of an air conditioner according to embodiment 7. FIG. 19 is a perspective view of an outdoor unit of an air conditioner according to embodiment 7, as seen from the air outlet side. FIG. 19 is a diagram for explaining the configuration of the outdoor unit from the top side. FIG. 19 is a diagram showing a state in which a fan grill has been removed from the outdoor unit.FIG. 2 is a diagram showing the internal configuration of the outdoor unit with the fan grille, front panel, etc. removed.

[0011] An axial fan, a blower, and an air conditioner according to embodiments will be described below with reference to the drawings. Note that in the following drawings, including FIG. 1 , the relative dimensional relationships and shapes of the components may differ from those in reality. In the following drawings, identical reference numerals denote identical or equivalent components, and this applies throughout the entire specification. To facilitate understanding, directional terms (e.g., "up," "down," "right," "left," "front," and "rear") are used as appropriate. However, these terms are used merely for the sake of convenience and do not limit the arrangement or orientation of the device or components.

[0012] Embodiment 1. [Axial Fan 100] Figure 1 is a front view showing the schematic configuration of an axial fan 100 according to embodiment 1. The rotational direction DR indicated by the arrow in the figure indicates the direction in which the axial fan 100 rotates. The counter-rotational direction OR indicated by the arrow in the figure indicates the direction opposite to the rotational direction of the axial fan 100. Furthermore, the circumferential direction CD indicated by the double-headed arrow in the figure indicates the circumferential direction of the axial fan 100. The circumferential direction CD includes the rotational direction DR and the counter-rotational direction OR.

[0013] 1 is a direction perpendicular to the rotation axis RA of the axial fan 100 and represents the radial direction of the axial fan 100. In the radial direction, the Y2 side portion is located on the outer periphery side of the Y1 side portion, and the Y1 side portion is located on the inner periphery side of the Y2 side portion. In other words, the Y1 side of the axial fan 100 is the inner periphery side of the axial fan 100, and the Y2 side of the axial fan 100 is the outer periphery side of the axial fan 100.

[0014] An axial fan 100 according to a first embodiment will be described with reference to Figure 1. The axial fan 100 is an axial impeller and is a device that creates a fluid flow. The axial fan 100 is used in a blower 55 (see Figure 31), which will be described later, and is used, for example, as a fan in an air conditioner, a ventilation device, or the like. The axial fan 100 creates a fluid flow by rotating in a rotation direction DR about a rotation axis RA. The fluid is, for example, a gas such as air, and the axial fan 100 creates an airflow by rotating.

[0015] The front side of the paper in Fig. 1 is the downstream side of the axial fan 100 in the direction of fluid flow, and the back side of the paper in Fig. 1 is the upstream side of the axial fan 100 in the direction of fluid flow. Therefore, Fig. 1 is a view of the axial fan 100 as seen from the downstream side in the direction of fluid flow. The upstream side of the axial fan 100 is the air intake side of the axial fan 100, and the downstream side of the axial fan 100 is the air blowing side of the axial fan 100.

[0016] 1, the axial flow fan 100 includes a hub 10 connected to a rotating shaft that is rotated by a drive source such as a motor (not shown), and a plurality of blades 20 that extend radially outward from the hub 10. The axial flow fan 100 includes a so-called bossless fan in which the leading edge and trailing edge portions of adjacent blades 20 are connected to form a continuous surface without a boss.

[0017] (Hub 10) The hub 10 is connected to the rotating shaft of a drive source such as a motor (not shown). The hub 10 may be configured, for example, in a cylindrical shape or in a plate shape such as a disk. The shape of the hub 10 is not limited as long as it can be connected to the rotating shaft of the drive source as described above.

[0018] The hub 10 is driven to rotate by a motor (not shown) or the like to form a rotation axis RA. The hub 10 rotates around the rotation axis RA. The rotation direction DR of the axial fan 100 is clockwise, as indicated by the arrow in FIG. 1 . However, the rotation direction DR of the axial fan 100 is not limited to clockwise. The hub 10 may also rotate counterclockwise by changing the mounting angle of the blades 20, the orientation of the blades 20, or the like.

[0019] (Blades 20) The blades 20 are provided around the hub 10 and are formed to extend radially outward from the hub 10. The blades 20 are arranged radially outward from the hub 10. The blades 20 are spaced apart from one another in the circumferential direction CD. Although the first embodiment illustrates an axial fan 100 having three blades 20, the number of blades 20 is not limited to three.

[0020] The blades 20 are formed in the same shape around the hub 10. The blades 20 are also arranged at equal intervals in the circumferential direction CD. However, the blades 20 are not limited to this configuration. The blades 20 may be formed in different shapes, or may be arranged at different intervals in the circumferential direction CD.

[0021] The blade 20 is formed in the shape of a forward-swept blade in which the outer peripheral portion protrudes further forward in the direction of rotation DR than the inner peripheral portion. Note that the blade 20 is not limited to a forward-swept blade and may be formed in other shapes. When viewed in the axial direction of the rotation axis RA, the blade 20 is formed in a substantially triangular shape in which the width in the circumferential direction CD of the outer peripheral portion is larger than the width in the circumferential direction CD of the inner peripheral portion. Note that the blade 20 is not limited to being formed in a substantially triangular shape when viewed in the axial direction of the rotation axis RA.

[0022] The blade 20 has a leading edge 21, a trailing edge 22, an inner edge 24 that is a portion that connects to the hub 10, and an outer edge 23 that forms the outer edge between the leading edge 21 and the trailing edge 22. The leading edge 21 is formed on the portion of the blade 20 that is on the forward side in the direction of rotation DR. In other words, the leading edge 21 is located forward of the trailing edge 22 in the direction of rotation DR. The leading edge 21 is located upstream of the trailing edge 22 in the flow direction of the fluid to be generated.

[0023] The trailing edge 22 is formed on the blade 20 at a portion on the rearward side in the direction of rotation DR. That is, the trailing edge 22 is located rearward of the leading edge 21 in the direction of rotation DR. The trailing edge 22 is located downstream of the leading edge 21 in the direction of flow of the fluid to be generated. The axial fan 100 has the leading edge 21 as a blade tip facing the direction of rotation DR of the axial fan 100, and the trailing edge 22 as a blade tip on the opposite side of the leading edge 21 in the direction of rotation DR.

[0024] The outer edge 23 extends forward and backward in the direction of rotation DR to define the portion between the outermost periphery of the leading edge 21 and the outermost periphery of the trailing edge 22. The outer edge 23 defines the outermost end of the axial fan 100 in the radial direction (Y-axis direction). The outer edge 23 defines the outer periphery of the blade 20, and also defines the outer periphery of the axial fan 100.

[0025] The outer edge portion 23 is formed in an arc shape when viewed in a direction parallel to the rotation axis RA. However, the outer edge portion 23 is not limited to a configuration in which it is formed in an arc shape when viewed in a direction parallel to the rotation axis RA. Note that the outer edge portion 23 includes a portion that is formed in an arc shape when viewed in a direction parallel to the rotation axis RA.

[0026] When viewed in a direction parallel to the rotation axis RA, the blade 20 is formed so that the length of the outer edge portion 23 in the circumferential direction CD is longer than the length of the inner edge portion 24 in the circumferential direction CD. However, the relationship between the length of the outer edge portion 23 and the length of the inner edge portion 24 in the circumferential direction CD of the blade 20 is not limited to this configuration. For example, the length of the outer edge portion 23 and the length of the inner edge portion 24 in the circumferential direction CD of the blade 20 may be equal, or the length of the inner edge portion 24 may be longer than the length of the outer edge portion 23.

[0027] The inner edge portion 24 extends forward and backward in the direction of rotation DR to define the portion between the innermost periphery of the leading edge portion 21 and the innermost periphery of the trailing edge portion 22. The inner edge portion 24 defines the inner end portion in the radial direction (Y-axis direction) of the axial flow fan 100. The inner edge portion 24 forms the inner peripheral edge of the blade 20 and defines the root portion of the blade 20.

[0028] The inner edge portion 24 is formed in an arc shape when viewed in a direction parallel to the rotation axis RA. However, the inner edge portion 24 is not limited to a configuration in which it is formed in an arc shape when viewed in a direction parallel to the rotation axis RA. The inner edge portion 24 of the blade 20 is connected to the hub 10, for example, by being formed integrally with the hub 10. As an example, the inner edge portion 24 of the blade 20 is formed integrally with the outer peripheral wall of the hub 10, which is formed in a cylindrical shape.

[0029] The blades 20 are formed at an angle with respect to a plane perpendicular to the rotation axis RA. The blades 20 transport the fluid by pushing the fluid present between the blades 20 with blade surfaces 28 as the axial fan 100 rotates. In this case, the surface of the blade surfaces 28 of the blades 20 that pushes the fluid and increases pressure when the axial fan 100 rotates is called a positive pressure surface 25, and the surface behind the positive pressure surface 25 and on which pressure decreases is called a negative pressure surface 26.

[0030] With respect to the blade surface 28, the surface facing the upstream side of the blade 20 in the direction of fluid flow is the suction surface 26, and the surface facing the downstream side is the pressure surface 25. The pressure surface 25 is the surface facing the direction of rotation DR, and the suction surface 26 is the surface facing the opposite side to the direction of rotation DR. With respect to the blade 20 in Figure 1, the surface on the front side of the blade 20 is the pressure surface 25, and the surface on the rear side of the blade 20 is the suction surface 26.

[0031] (Details of Blade 20) Figure 2 is a front view of blade 20 of axial fan 100 according to embodiment 1. Note that, in order to explain the configuration of blade 20, only one of the multiple blades 20 is shown in Figure 2, and the other blades 20 are not shown. A cylindrical surface CS indicated by a dotted line in Figure 2 indicates the position of an imaginary cylindrical surface whose radius is the outermost diameter of axial fan 100 and whose center is rotation axis RA when axial fan 100 is viewed in the axial direction of rotation axis RA.

[0032] The imaginary cylindrical surface CS indicates the position of the blade 20 that forms the outermost diameter of the axial fan 100, and shows the rotation trajectory of the part that forms the outermost diameter of the axial fan 100 when the axial fan 100 rotates. The part of the blade 20 that forms the imaginary cylindrical surface CS is the outer edge 23 of the blade 20. The structure of the blade 20 will be described in further detail using Figure 2. The blade 20 has a reduced portion 23a and an outer periphery 30.

[0033] (Converging section 23a) The blades 20 have a converging section 23a on the outer periphery of the axial fan 100, which forms the outer edge of the axial fan 100. The axial fan 100 has the converging section 23a, and the axial fan 100 has a region where the fan diameter is constricted on the leading edge side of the outer edge of the fan.

[0034] The reduced portion 23a of the blade 20 forms a portion on the leading edge 21 side of the portion forming the outer edge 23 where the outer diameter of the blade 20 is reduced compared to the portion on the trailing edge 22 side which forms the maximum diameter of the blade 20. The reduced portion 23a is formed on the outer edge 23 of the blade 20.

[0035] The outer edge portion 23 has a tip portion 201, an inflection portion 202, and a trailing end portion 203. The tip portion 201 is the portion of the outer edge portion 23 that is located closest to the leading edge portion 21 and is the boundary portion with the leading edge portion 21. The inflection portion 202 is the portion of the outer edge portion 23 that forms the outermost diameter of the blade 20 and is located closest to the tip portion 201. The trailing end portion 203 is the portion of the outer edge portion 23 that is located closest to the trailing edge portion 22 and is the boundary portion with the trailing edge portion 22.

[0036] The reduced portion 23a is formed between the leading edge 201 and the trailing edge 203, and is formed from the leading edge 201 toward the trailing edge 203. The leading edge 201 of the reduced portion 23a of the blade 20 is the portion closest to the leading edge 21. In other words, the reduced portion 23a includes the leading edge 201.

[0037] The reduced section 23a is formed so that the outer diameter of the blade 20 is smaller at the portion located on the leading edge 21 side than at the portion located on the trailing edge 22 side. In other words, the reduced section 23a is formed so that the outer diameter of the blade 20 is larger at the portion located on the trailing edge 22 side than at the portion located on the leading edge 21 side. The outer diameter of the blade 20 is the outer diameter of the axial flow fan 100 centered on the rotation axis RA, and is the distance between the rotation axis RA and the outer edge 23 of the blade 20 in the radial direction of the axial flow fan 100 when viewed in the axial direction of the rotation axis RA.

[0038] The reduced portion 23a is formed, for example, in the circumferential direction CD, such that the outer diameter of the blade 20 gradually decreases from a portion located on the trailing edge portion 22 side toward a portion located on the leading edge portion 21 side. That is, the reduced portion 23a is formed such that the outer diameter of the blade 20 gradually decreases toward the rotation direction DR. The reduced portion 23a is a portion formed such that the length of the blade 20 in the radial direction gradually decreases toward the rotation direction DR.

[0039] In other words, the reduced portion 23a is formed so that the outer diameter of the blade 20 gradually increases in the circumferential direction CD from the portion located on the leading edge portion 21 side toward the trailing edge portion 22. That is, the reduced portion 23a is formed so that the outer diameter of the blade 20 gradually increases in the direction opposite to the rotation direction DR. The reduced portion 23a is formed so that the length of the blade 20 in the radial direction gradually increases in the direction opposite to the rotation direction DR.

[0040] Note that the reduced portion 23a is not limited to a portion in which the outer diameter of the blade 20 gradually decreases from the portion located on the trailing edge 22 side toward the portion located on the leading edge 21 side in the circumferential direction CD. The reduced portion 23a may be formed so that, when the blade 20 is viewed as a whole, the outer diameter of the blade 20 portion at the tip 201 is smaller than that of the portion located on the trailing edge 22 side. The reduced portion 23a is not limited to a portion in which the outer diameter of the blade 20 gradually changes in the circumferential direction CD, and may include a radially recessed portion or a radially protruding portion. However, the outer diameter of the reduced portion 23a is formed smaller than the outermost diameter of the blade 20.

[0041] The blade 20 is formed with a notched shape at the reduced portion 23a compared to a virtual outer edge 23 located on the cylindrical surface CS, which would be the outer edge 23 of the blade 20 if the blade 20 did not have the reduced portion 23a. As shown in Figure 2, the reduced portion 23a is formed so as to be located on the inner peripheral side (Y1 side) of the cylindrical surface CS, closer to the rotation axis RA.

[0042] The reduced portion 23a of the blade 20 is formed such that, when viewed in the axial direction of the rotation axis RA, the width between the cylindrical surface CS and the outer edge portion 23 in the radial direction centered on the rotation axis RA decreases from the tip portion 201 toward the trailing edge portion 22. In other words, the reduced portion 23a of the blade 20 is formed such that, when viewed in the axial direction of the rotation axis RA, the width between the cylindrical surface CS and the outer edge portion 23 in the radial direction centered on the rotation axis RA increases from the portion located on the trailing edge portion 22 side toward the tip portion 201.

[0043] The reduced portion 23a is formed in a portion of the outer edge portion 23 on the leading edge portion 21 side in the circumferential direction CD. The reduced portion 23a is formed in the circumferential direction CD from the tip portion 201 to the inflection portion 202. The reduced portion 23a is formed in the entire region between the tip portion 201 and the inflection portion 202 in the circumferential direction CD centered on the rotation axis RA.

[0044] The inflection portion 202 is provided in the outer edge portion 23 between the leading edge portion 201 and the trailing edge portion 203. Alternatively, the inflection portion 202 may be provided at the same position as the trailing edge portion 203. The reduced portion 23 a may be formed in a portion of the outer edge portion 23 on the leading edge portion 21 side in the circumferential direction CD, or may be formed from the leading edge portion 21 to the trailing edge portion 22.

[0045] The inflection portion 202 is a portion of the outer edge 23 of the blade 20 that forms a different curvature with respect to the cylindrical surface CS. The inflection portion 202 is a portion of the outer edge 23 of the blade 20 that forms a curvature that is larger than the curvature of the cylindrical surface CS. The inflection portion 202 is a portion where the curvature changes between the portion that forms the maximum diameter of the blade 20 and the portion that forms the leading edge 21 side of that. The inflection portion 202 is a portion that forms the outermost diameter of the axial fan 100 and the blade 20, and is a portion that is located on the imaginary cylindrical surface CS when viewed in the axial direction of the rotation axis RA. The inflection portion 202 is a boundary between the contraction portion 23a and the rear outer edge portion 23b, which will be described later. In other words, the inflection portion 202 is the rear end portion of the contraction portion 23a and the tip portion of the rear outer edge portion 23b.

[0046] When the positions of the inflection point 202 and the trailing end 203 are different, the outer edge 23 of the blade 20 includes a rear outer edge 23b between the inflection point 202 and the trailing end 203. The blade 20 has the rear outer edge 23b at a portion of the outer edge 23 that is closer to the trailing edge 22 than the reduced portion 23a. The rear outer edge 23b is a portion of the blade 20 that is formed so that the outer diameter is constant.

[0047] The rear outer edge 23b is a portion of the outer edge 23 that forms a constant outer diameter from a portion located on the leading edge 21 side to a portion located on the trailing edge 22 side. The rear outer edge 23b is a portion that is formed along the cylindrical surface CS when viewed in the axial direction of the rotation axis RA. The rear outer edge 23b is a portion that forms the outermost diameter of the axial fan 100 and the blade 20. The rear outer edge 23b may be formed in a portion between the inflection portion 202 and the rear end portion 203, or may be formed in the entire portion between the inflection portion 202 and the rear end portion 203.

[0048] The blade 20 may include a portion whose shape does not follow the cylindrical surface CS in the outer edge 23 that constitutes the portion between the inflection portion 202 and the rear end 203. For example, when viewed in the axial direction of the rotation axis RA, the blade 20 may include a portion that is formed linearly in the outer edge 23 that constitutes the portion between the inflection portion 202 and the rear end 203. Furthermore, when viewed in the axial direction of the rotation axis RA, the blade 20 may include a portion in which the outer diameter of the blade 20 is smaller than the outermost diameter of the blade 20 in part of the outer edge 23 that constitutes the portion between the inflection portion 202 and the rear end 203.

[0049] (Outer periphery 30) Figure 3 is a cross-sectional view of the blade 20 of the axial fan 100 according to the first embodiment. Figure 3 is a cross-sectional view of the blade 20 taken along line A-A in Figure 2, viewed in the direction of the arrows. The outer periphery 30 of the blade 20 will be described using Figures 2 and 3. In the contracting section 23a, the outer periphery 30 forms a pressure surface 25 that curves from the downstream side to the upstream side in the direction of the flow of fluid that flows when the blade 20 rotates, as it moves from the inner periphery 24 side toward the outer periphery 23.

[0050] The outer peripheral portion 30 functions to reduce tip vortices or shift their generation direction upward by rectifying the airflow around the tip of the blade 20 on the outer periphery, thereby reducing air resistance. The outer peripheral portion 30 is formed in the contracting portion 23a. The outer peripheral portion 30 is also formed along the outer edge 23 of the blade 20. The outer peripheral portion 30 is formed from the outer edge 23 to a specific portion on the inner edge 24 side in the radial direction centered on the rotation axis RA.

[0051] The outer peripheral portion 30 is a portion of the blade 20 that forms the outer peripheral pressure surface 25a. The pressure surface 25 of the blade 20 includes the outer peripheral pressure surface 25a. As shown in FIG. 2 , the outer peripheral pressure surface 25a forms a surface facing outward of the blade 20. The outer peripheral pressure surface 25a forms a surface that has a radial component centered on the rotation axis RA. The outer peripheral pressure surface 25a forms a surface on the side of the axial flow fan 100.

[0052] Outer peripheral positive pressure surface 25a is formed so as to curve from downstream to upstream in the direction of fluid flow formed by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23. Alternatively, outer peripheral positive pressure surface 25a is formed so as to curve up from downstream to upstream in the direction of fluid flow formed by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23. Outer peripheral positive pressure surface 25a is formed so that the downstream and outer peripheral sides bulge.

[0053] The outer circumferential portion 30 is formed in the reduced portion 23a, and for example, is formed in the circumferential direction CD from the tip portion 201 to the inflection portion 202. The outer circumferential portion 30 is formed in the entire region of the reduced portion 23a in the circumferential direction CD centered on the rotation axis RA. The outer circumferential portion 30 is also formed so that the radial width W centered on the rotation axis RA is larger in the portion on the trailing edge portion 22 side than in the portion on the leading edge portion 21 side.

[0054] As an example, the outer peripheral portion 30 is formed so that the radial width W about the rotation axis RA gradually increases from the tip portion 201 toward the inflection portion 202. That is, the outer peripheral portion 30 is formed so that the radial width W about the rotation axis RA gradually increases from the portion on the tip portion 201 side toward the portion on the trailing edge portion 22 side. The outer peripheral portion 30 is formed so that the radial width W gradually increases from the portion on the leading edge portion 21 side toward the portion on the trailing edge portion 22 side.

[0055] The width W of the outer peripheral portion 30 shown in Fig. 2 is the width W1 in the radial direction centered on the rotation axis RA when viewed in the axial direction of the rotation axis RA (see Fig. 3). Note that the width W of the outer peripheral portion 30 may also be defined as the width W2 along the positive pressure surface 25 in the radial direction centered on the rotation axis RA, as shown in Fig. 3.

[0056] The cylindrical surface CL indicated by the dotted line in Figure 2 is a cylindrical surface having a radius centered on the rotation axis RA when the axial flow fan 100 is viewed in the axial direction of the rotation axis RA, and indicates the position of an imaginary cylindrical surface that passes through the tip end 201. In the blade 20 shown in Figure 2, the outer peripheral portion 30 is formed in a range between the imaginary cylindrical surface CL and the outer edge portion 23 in the radial direction centered on the rotation axis RA. Note that the position where the outer peripheral portion 30 is formed is not limited to this range, and the inner peripheral portion of the outer peripheral portion 30 may be formed up to a position closer to the inner edge 24 than the cylindrical surface CL. In other words, the range where the outer peripheral portion 30 is formed in the blade 20 may include the position where the cylindrical surface CL is formed.

[0057] The blade 20 has an outer peripheral pressure surface 25a that curves upward toward the upstream side as it approaches the outer periphery in the radial direction at the outer peripheral portion 30. The outer peripheral portion 30 is formed in a reduction section 23a, which is a region where the blade diameter is reduced, from an arbitrary position on the leading edge portion 21 side to an inflection section 202 that reaches the maximum diameter. The radial width W of the outer peripheral portion 30 is larger at the portion on the inflection section 202 side that forms the maximum diameter of the blade 20 than at an arbitrary position on the leading edge portion 21 side.

[0058] 4 is a front view of a first modified example of the blade 20 of the axial fan 100 according to embodiment 1. The outer circumferential portion 30 only needs to be formed in the contracted portion 23a, and is not limited to being formed in the entire region in the circumferential direction CD from the tip 201 to the inflection portion 202. The outer circumferential portion 30 may also be formed in a portion of the contracted portion 23a in the circumferential direction CD about the rotation axis RA.

[0059] The outer circumferential portion 30 may be formed rearward of the tip portion 201, i.e., in a portion closer to the trailing edge portion 22 than the tip portion 201. As shown in Fig. 4 , the outer circumferential portion 30 may be formed in the circumferential direction CD from a position closer to the inflection portion 202 than the tip portion 201 to the position of the inflection portion 202, without including the tip portion 201. In other words, the outer circumferential portion 30 may be formed in the entire region between a specific position between the tip portion 201 and the inflection portion 202 and the position of the inflection portion 202 in the circumferential direction CD.

[0060] 5 is a front view of a second modified example of blade 20 in axial fan 100 according to embodiment 1. As described above, outer circumferential portion 30 may be formed in a partial region of reduced portion 23 a in circumferential direction CD about rotation axis RA.

[0061] 5 , the outer circumferential portion 30 may be formed in the counter-rotation direction OR from the tip portion 201 to just before the inflection portion 202, without including the inflection portion 202. In other words, the outer circumferential portion 30 may be formed in the entire region between the position of the tip portion 201 and a specific position between the tip portion 201 and the inflection portion 202 in the circumferential direction CD.

[0062] 6 is a front view of a third modified example of blade 20 in axial fan 100 according to embodiment 1. As described above, outer circumferential portion 30 may be formed in a partial region of reduced portion 23 a in circumferential direction CD about rotation axis RA.

[0063] 6 , the outer circumferential portion 30 may be formed in a region between the tip portion 201 and the inflection portion 202 in the circumferential direction CD, without including the tip portion 201 and the inflection portion 202. In other words, the outer circumferential portion 30 may be formed from a specific position on the leading edge portion 21 side to a specific position on the trailing edge portion 22 side, between the tip portion 201 and the inflection portion 202 in the circumferential direction CD.

[0064] 7 is a front view of a fourth modified example of blade 20 in axial fan 100 according to embodiment 1. The formation region of outer periphery 30 is located rearward of tip 201, and outer periphery 30 is formed so that width W gradually increases from tip 201 toward inflection point 202. As shown in FIG. 7 , outer periphery 30 may be formed in a triangular shape with one of its vertices at the tip end on the leading edge 21 side when viewed in the axial direction of rotation axis RA.

[0065] Figure 8 is a front view of a fifth modified example of the blade 20 of the axial fan 100 according to embodiment 1. The number of outer circumferential portions 30 in the reduced section 23a of the blade 20 in Figures 1 to 7 is one. The number of outer circumferential portions 30 in the reduced section 23a of the blade 20 is not limited to one, and may be multiple as shown in Figure 8. In other words, the reduced section 23a of the blade 20 may have one outer circumferential portion 30 or multiple outer circumferential portions 30.

[0066] FIG. 9 is a front view of a sixth modified example of the blade 20 of the axial fan 100 according to the first embodiment. FIG. 10 is a front view of a seventh modified example of the blade 20 of the axial fan 100 according to the first embodiment. The change in diameter at the contracted portion 23 a of the blade 20 may be nonlinear. That is, the change in diameter at the contracted portion 23 a of the blade 20 in the direction of rotation DR does not have to be a simple decrease, and the change in diameter at the opposite direction of rotation OR does not have to be a simple increase. When comparing the portion of the contracted portion 23 a on the tip end 201 side with the portion on the trailing edge 22 side, it is sufficient that the outer diameter of the portion on the tip end 201 side of the contracted portion 23 a as a whole is smaller than the outer diameter of the portion on the trailing edge 22 side.

[0067] The narrowing portion 23 a is not limited to a shape in which the diameter gradually increases in the counter-rotation direction OR, but may have a recessed portion 23 c between the tip portion 201 and the inflection portion 202 that is recessed compared to the shape in which the diameter gradually increases, as shown in FIG. 9 .

[0068] 10, the reduced portion 23a may have a protruding portion 23d between the tip 201 and the inflection portion 202 that protrudes compared to the shape in which the diameter gradually increases in the counter-rotation direction OR. However, the outer diameter of the protruding portion 23d is smaller than the maximum diameter of the blade 20.

[0069] The outer edge 23 of the reduced portion 23a is not limited to a curved shape and may include a straight portion. Also, the outer edge 23 of the reduced portion 23a may be formed in a wavy line shape or a sawtooth shape.

[0070] Operation of the Axial Fan 100 When the axial fan 100 rotates in the rotation direction DR shown in Figure 1 , each blade 20 pushes out surrounding air with its pressure surface 25. This causes the fluid to flow in a direction perpendicular to the plane of the paper in Figure 1 . More specifically, when the axial fan 100 rotates in the rotation direction DR shown in Figure 1 , a flow of fluid is generated from the back of the paper to the front of the paper in Figure 1 . Furthermore, when the axial fan 100 rotates, the pressure on the suction surface 26 side becomes smaller than the pressure on the pressure surface 25 side, and a pressure difference occurs between the pressure surface 25 side and the suction surface 26 side around each blade 20.

[0071] [Effects of the Axial Fan 100] Fig. 11 is a conceptual diagram of a radial cross section of an axial fan 100L according to a comparative example. The axial fan 100L is a commonly used fan. First, an image of the formation of a blade tip vortex WL formed in a typical axial fan 100L will be described with reference to Fig. 11 .

[0072] Typically, when the axial fan 100L rotates, a pressure difference occurs between the suction surface 26, which is the upstream surface on the blade surface, and the pressure surface 25, which is the downstream surface, in the direction of fluid flow caused by the axial fan 100L. At the outer edge of the axial fan 100L, a blade tip vortex WL is generated when the fluid flow leaks from the pressure surface 25 to the suction surface 26 due to the pressure difference. The blade tip vortex WL gradually accumulates and expands from the leading edge 21 to the trailing edge 22 of the blade 20, enlarging the vortex diameter.

[0073] Fig. 12 is a perspective view of an axial fan 100R according to a second comparative example. Fig. 13 is a side view of the axial fan 100R according to the second comparative example. The axial fan 100R is a fan that has a bent portion 140, like the fan disclosed in Patent Document 1.

[0074] The axial flow fan 100R has a bent portion 140 at the outer periphery of each blade 20R that is bent upward toward the suction side, and the radial width of the bent portion 140 is formed so that it gradually increases from the leading edge 21 toward the trailing edge 22. With this configuration, the axial flow fan 100R can smoothly guide the blade tip vortex WL from the leading edge 21 toward the trailing edge 22, and the generated blade tip vortex WL is less likely to leave the suction surface 26 of the blade 20.

[0075] The blade tip vortex WL is generated at the outer edge 23 from the leading edge 21 side and flows rearward while gradually expanding. As described above, in the axial flow fan 100R, the size of the bent portion 140 gradually increases from the leading edge 21 side toward the trailing edge 22 side, so that the expanding blade tip vortex WL can be guided along the bent portion 140, and the blade tip vortex WL is stabilized without being disturbed.

[0076] In a state where there is no structure upstream of the axial fan 100R in the direction of fluid flow caused by the axial fan 100R, or where the axial fan 100R is located away from a structure disposed upstream of the axial fan 100R, a less turbulent airflow flows into the axial fan 100R. Therefore, in a state where there is no structure upstream of the axial fan 100R, the blade tip vortex WL generated at the leading edge 21 side is smaller than the blade tip vortex WL generated at the trailing edge 22 side, and the axial fan 100R does not need to take into consideration the influence of the blade tip vortex WL generated at the leading edge 21 side.

[0077] Fig. 14 is a conceptual diagram of an outdoor unit 150R used in an air conditioner equipped with an axial fan 100R according to a second comparative example. Fig. 15 is a conceptual diagram showing the relationship between the motor support 155 and the axial fan 100R in the outdoor unit 150R used in the air conditioner shown in the comparative example of Fig. 14. Next, the effect of the wake WT of a structure on the blade tip vortex WL will be described using the outdoor unit 150R used in an air conditioner.

[0078] The outdoor unit 150R used in an air conditioner is a device that conditions the air by adjusting the temperature and humidity of the air in the indoor space to be air-conditioned. The outdoor unit 150R is a refrigeration cycle device that forms a refrigerant circuit in which a compressor 153, a condenser, an expansion valve, an evaporator, etc. are connected by piping. The outdoor unit 150R houses a heat exchanger 152 that functions as a condenser or evaporator, and an axial fan 100R inside a housing 151, and is installed outdoors.

[0079] The air conditioner 150 includes an axial fan 100R, a heat exchanger 152, and a housing 151 that houses the axial fan 100R and the heat exchanger 152. The axial fan 100R is connected to a motor 154. The motor 154 is fixed to a motor support 155. The motor support 155 is a structure that is located upstream of the axial fan 100R in the direction of fluid flow caused by the axial fan 100R.

[0080] 14 and 15 , when a structure such as the motor support 155 is present, the wake WT flowing downstream of the structure is disturbed by the structure, and therefore the structure such as the motor support 155 located upstream of the axial fan 100R causes disturbances in the flow of the fluid flowing into the axial fan 100R.

[0081] When a turbulent fluid flow such as the wake WT flows into the leading edge 21 on the outer periphery of the axial fan 100R, the peripheral velocity of the outer edge 23 located at the outermost periphery of the blade 20 causes a large leakage of fluid even at the leading edge 21 of the blade 20, increasing the formation of a blade tip vortex WL. The outer edge 23 located at the outermost periphery of the blade 20 is the part of the axial fan 100R where the peripheral velocity is the fastest in the radial direction. When a turbulent wake WT caused by the motor support 155 or the like flows into the leading edge 21 of the outer edge, a large blade tip vortex WL is formed even at the leading edge 21, due to the large influence of the peripheral velocity. Note that the peripheral velocity of the blade 20 decreases as it approaches the rotation axis RA and increases as it moves away from the rotation axis RA.

[0082] If the portion on the leading edge 21 side is simply formed with a small upward curve, as in the case of the bent portion 140 of the axial flow fan 100R, there is a risk that the blade tip vortex WL will not be stabilized when a turbulent fluid flow such as the wake WT flows into the axial flow fan 100R, resulting in reduced fan efficiency.

[0083] The blade 20 of the axial flow fan 100 has a reduced section 23a at the leading edge 21 side of the portion forming the outer edge 23, where the outer diameter of the blade 20 is reduced compared to the trailing edge 22 side, which forms the maximum diameter of the blade 20. The blade 20 of the axial flow fan 100 also has an outer peripheral portion 30 at the reduced section 23a that forms a positive pressure surface 25 that curves from the downstream side to the upstream side in the flow direction of the fluid that flows when the blade 20 rotates, as it moves from the inner edge 24 side toward the outer edge 23. The outer peripheral portion 30 is formed so that the radial width W, centered on the rotation axis RA, is larger at the trailing edge 22 side than at the leading edge 21 side.

[0084] In the axial flow fan 100, the blades 20 have a reduced diameter on the leading edge 21 side due to the reduced diameter portion 23a, and the portion on the leading edge 21 side is closer to the rotation axis RA than the portion of the blade 20 forming the outermost diameter. This reduces the circumferential velocity of the portion of the blade 20 on the leading edge 21 side. Therefore, even if a turbulent fluid flow flows into the axial flow fan 100 due to a structure such as a motor support, the circumferential velocity on the leading edge 21 side of the blade 20 is low, so that the blade tip vortex WL formed on the portion of the blade 20 on the leading edge 21 side is small. Furthermore, the axial flow fan 100 has an outer circumferential portion 30 at the reduced portion 23a. The outer circumferential portion 30 is formed so that the radial width W of the outer circumferential portion 30, centered on the rotation axis RA, is larger on the trailing edge 22 side than on the leading edge 21 side. With this configuration, the axial fan 100 can cause the blade tip vortex WL, which expands from the leading edge 21 toward the trailing edge 22, to follow the outer periphery 30. Therefore, the blade tip vortex WL on the suction surface 26 of the axial fan 100 is stable and not turbulent, improving fan efficiency and achieving high efficiency.

[0085] Alternatively, the outer circumferential portion 30 may be formed in a partial region of the contraction section 23a in the circumferential direction CD about the rotation axis RA. The axial fan 100 has the outer circumferential portion 30 in a part of the contraction section 23a, and the outer circumferential portion 30 is formed so that its radial width W about the rotation axis RA is larger at the trailing edge 22 side than at the leading edge 21 side. By having this configuration, the axial fan 100 can guide the blade tip vortex WL, which expands from the leading edge 21 side toward the trailing edge 22 side, along the outer circumferential portion 30. Therefore, the blade tip vortex WL on the suction surface 26 of the axial fan 100 is stable and not turbulent, improving fan efficiency and achieving high efficiency.

[0086] Alternatively, the outer circumferential portion 30 may be formed over the entire region of the contraction section 23a in the circumferential direction CD centered on the rotation axis RA. The axial fan 100 has the outer circumferential portion 30 over the entire region of the contraction section 23a, and the outer circumferential portion 30 is formed so that its radial width W about the rotation axis RA is larger at the trailing edge 22 side than at the leading edge 21 side. This configuration allows the axial fan 100 to guide the blade tip vortex WL, which expands from the leading edge 21 side toward the trailing edge 22 side, along the outer circumferential portion 30. Therefore, the axial fan 100 stabilizes the blade tip vortex WL on the suction surface 26 without turbulence, improving fan efficiency and achieving high efficiency. Here, the peripheral speed of the blade 20 increases as the diameter increases. The entire region of the contraction section 23a is the region from the tip 201 to the inflection portion 202. The inflection portion 202 is the portion of the blade 20 that forms the maximum diameter, and is the portion of the blade 20 where the peripheral speed is faster than that of the tip portion 201. By forming the outer circumferential portion 30 from the tip portion 201 to the inflection portion 202, the axial flow fan 100 can further improve the stability of the blade tip vortex WL.

[0087] Furthermore, outer circumferential portion 30 is formed so that its radial width W, centered on rotation axis RA, gradually increases from the portion on the tip end 201 side toward the portion on the trailing edge 22 side. With this configuration, axial fan 100 can further direct the blade tip vortex WL, which expands from the portion on the leading edge 21 side toward the portion on the trailing edge 22 side, along outer circumferential portion 30. Therefore, in axial fan 100, the blade tip vortex WL on suction surface 26 is stabilized without being disturbed, improving fan efficiency and achieving high efficiency.

[0088] Second Embodiment Figure 16 is a front view of a blade 20 in an axial fan 100 according to a second embodiment. Figure 17 is a cross-sectional view of the blade 20 in an axial fan 100 according to the second embodiment. In order to explain the configuration of the blade 20, Figure 16 shows only one of the multiple blades 20, with the other blades 20 not shown. Figure 17 is a cross-sectional view of the blade 20 taken along line B-B in Figure 16, viewed in the direction of the arrows. Note that parts having the same configuration as those in the axial fan 100 of Figures 1 to 10 are designated by the same reference numerals, and their description will be omitted. The axial fan 100 according to the second embodiment further specifies the configuration of the rear outer edge portion 23b.

[0089] The rear outer edge portion 23b may have a rear outer peripheral portion 40. That is, the blade 20 may further have the rear outer peripheral portion 40 in addition to the outer peripheral portion 30. The rear outer peripheral portion 40 forms a pressure surface 25 that curves from the downstream side to the upstream side in the flow direction of the fluid that flows when the blade 20 rotates, from the portion on the inner edge portion 24 side toward the outer edge portion 23, on the trailing edge portion 22 side of the reduced portion 23a.

[0090] The rear outer peripheral portion 40 is formed in the area of ​​the rear outer edge portion 23 b. The rear outer peripheral portion 40 is formed rearward of the outer peripheral portion 30 in the direction of rotation DR, and is formed in a portion closer to the rear edge portion 22 than the outer peripheral portion 30.

[0091] Similar to the outer peripheral portion 30, the rear outer peripheral portion 40 functions to reduce the blade tip vortex WL by rectifying the airflow around the blade tip on the outer periphery of the blade 20, or by shifting the direction of generation upward, thereby reducing air resistance. The rear outer peripheral portion 40 is formed in the area of ​​the rear outer edge 23b. The rear outer peripheral portion 40 is also formed along the outer edge 23 of the blade 20. The rear outer peripheral portion 40 is formed from the outer edge 23 to a specific portion on the inner edge 24 side in the radial direction centered on the rotation axis RA.

[0092] The rear outer peripheral portion 40 is a portion of the blade 20 that forms the rear outer peripheral positive pressure surface 25b. The pressure surface 25 of the blade 20 includes the rear outer peripheral positive pressure surface 25b. As shown in FIG. 17 , the rear outer peripheral positive pressure surface 25b forms a surface that faces outward from the blade 20. The rear outer peripheral positive pressure surface 25b forms a surface that has a radial component centered on the rotation axis RA. The rear outer peripheral positive pressure surface 25b forms a surface on the side of the axial flow fan 100.

[0093] Rear outer peripheral positive pressure surface 25b is formed so as to curve from downstream to upstream in the direction of fluid flow formed by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23. Alternatively, rear outer peripheral positive pressure surface 25b is formed so as to curve up from downstream to upstream in the direction of fluid flow formed by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23. Rear outer peripheral positive pressure surface 25b is formed so that it bulges out on the downstream and outer peripheral sides.

[0094] 16 , the rear outer peripheral portion 40 is formed in the entire region from the inflection portion 202 to the rear end portion 203 in the circumferential direction CD. The rear outer peripheral portion 40 is formed rearward of the reduced portion 23a in the rotational direction DR, and is formed so as to extend from the inflection portion 202 to the rear edge portion 22.

[0095] The rear outer peripheral portion 40 is formed in a range between an imaginary cylindrical surface CL and the outer edge portion 23 in the radial direction centered on the rotation axis RA. The formation position of the rear outer peripheral portion 40 is not limited to this range, and the inner peripheral side portion of the rear outer peripheral portion 40 may be formed up to a position closer to the inner edge portion 24 than the cylindrical surface CL. In other words, the formation range of the rear outer peripheral portion 40 of the blade 20 may include the formation position of the cylindrical surface CL.

[0096] 18 is a front view of a first modified example of the blade 20 of the axial fan 100 according to embodiment 2. The rear outer peripheral portion 40 only needs to be formed on the rear outer edge portion 23b, and is not limited to being formed over the entire region from the inflection portion 202 to the rear end portion 203 in the circumferential direction CD.

[0097] The rear outer peripheral portion 40 may be formed rearward of the reduced portion 23a, i.e., in a portion closer to the trailing edge 22 than the reduced portion 23a. As shown in FIG. 18 , the rear outer peripheral portion 40 may be formed in the circumferential direction CD from a position closer to the trailing end 203 than the inflection portion 202 to the position of the trailing end 203, without including the inflection portion 202. That is, the rear outer peripheral portion 40 may be formed in the entire region between a specific position between the inflection portion 202 and the trailing end 203 and the position of the trailing end 203, in the circumferential direction CD. The rear outer peripheral portion 40 is formed rearward of the reduced portion 23a in the rotational direction DR, and is formed to extend from a position closer to the trailing end 203 than the inflection portion 202 to the trailing edge 22.

[0098] 19 is a front view of a second modified example of the blade 20 of the axial fan 100 according to the second embodiment. As shown in FIG. 19 , the rear outer peripheral portion 40 may be formed in the counter-rotation direction OR from the inflection portion 202 to just before the rear end 203, without including the rear end 203. That is, the rear outer peripheral portion 40 may be formed in the entire region in the circumferential direction CD between the position of the inflection portion 202 and a specific position between the inflection portion 202 and the rear end 203. The rear outer peripheral portion 40 is formed rearward of the reduced portion 23 a in the rotation direction DR, and extends from the portion on the leading edge 21 side to the portion on the trailing edge 22 side, but does not reach the trailing edge 22.

[0099] 20 is a front view of a third modified example of the blade 20 of the axial fan 100 according to the second embodiment. As shown in FIG. 20 , the rear outer peripheral portion 40 may be formed in the region between the inflection portion 202 and the rear end portion 203 in the circumferential direction CD, without including the inflection portion 202 and the rear end portion 203. That is, the rear outer peripheral portion 40 may be formed between the inflection portion 202 and the rear end portion 203 in the circumferential direction CD, from a specific position on the leading edge portion 21 side to a specific position on the trailing edge portion 22 side. The rear outer peripheral portion 40 is formed rearward of the reduced portion 23 a in the rotation direction DR, and extends from the portion on the leading edge portion 21 side to the portion on the trailing edge portion 22 side, but does not reach the trailing edge 22.

[0100] 21 is a front view of a fourth modified example of the blade 20 of the axial fan 100 according to embodiment 2. The rear outer peripheral portion 40 is formed so that the radial width BW about the rotation axis RA gradually increases from the portion on the inflection portion 202 side toward the portion on the rear end 203 side. That is, the rear outer peripheral portion 40 is formed so that the radial width W gradually increases from the portion on the leading edge 21 side toward the portion on the trailing edge 22 side. When viewed in the axial direction of the rotation axis RA, the rear outer peripheral portion 40 may be formed in a triangular shape with one of its vertices located at the tip end portion on the leading edge 21 side.

[0101] 22 is a front view of a fifth modified example of the blade 20 of the axial fan 100 according to the second embodiment. The rear outer peripheral portion 40 is formed so that the radial width BW about the rotation axis RA gradually decreases from the portion on the inflection portion 202 side toward the portion on the rear end portion 203 side. That is, the rear outer peripheral portion 40 is formed so that the radial width W gradually decreases from the portion on the leading edge portion 21 side toward the portion on the trailing edge portion 22 side. When viewed in the axial direction of the rotation axis RA, the rear outer peripheral portion 40 may be formed in a triangular shape with one of its vertices located at the tip end portion on the trailing edge portion 22 side.

[0102] [Effects of the Axial Fan 100] The blade 20 of the second embodiment further includes a rear outer peripheral portion 40 that forms a pressure surface 25 that curves from downstream to upstream in the direction of fluid flow when the blade 20 rotates, from the inner edge 24 toward the outer edge 23, closer to the trailing edge 22 than the contraction portion 23a. The rear outer peripheral portion 40 forms a pressure surface 25 that curves from downstream to upstream in the direction of fluid flow when the blade 20 rotates, as it extends from the inner edge 24 toward the outer edge 23. In the axial fan 100, the blade tip vortex WL stabilized by the contraction portion 23a and the outer peripheral portion 30 flows rearward. By including the rear outer peripheral portion 40, the axial fan 100 can continuously form a stabilized blade tip vortex WL, and can maintain the stability of the blade tip vortex WL until it is blown out from the blade 20. Therefore, the axial fan 100 stabilizes the blade tip vortex WL on the suction surface 26 without turbulence, improving fan efficiency and achieving high efficiency.

[0103] Third Embodiment Figure 23 is a front view of a blade 20 in an axial fan 100 according to a third embodiment. Figure 24 is a cross-sectional view of the blade 20 in an axial fan 100 according to the third embodiment. In order to explain the configuration of the blade 20, Figure 23 shows only one of the multiple blades 20, with the other blades 20 not shown. Figure 24 is a cross-sectional view of the blade 20 taken along line A-A in Figure 23, viewed in the direction of the arrows. Note that parts having the same configuration as those in the axial fan 100 of Figures 1 to 22 are given the same reference numerals, and their description will be omitted. The axial fan 100 according to the third embodiment further specifies the configuration of the outer circumferential portion 30.

[0104] In a radial cross section centered on rotation axis RA, outer peripheral portion 30 has first region 25a1 that includes outer edge portion 23 of the fan and second region 25a2 that is formed continuously with the first region 25a1 on the inner circumferential side of outer peripheral positive pressure surface 25a of outer peripheral portion 30.

[0105] The first region 25a1 forms an area located radially outward of the second region 25a2 in the radial direction of the axial fan 100, and includes the outer edge 23 of the blade 20. The second region 25a2 forms an area located radially inward of the first region 25a1 in the radial direction of the axial fan 100. The first region 25a1 and the second region 25a2 are formed continuously in the radial direction of the axial fan 100. The first region 25a1 and the second region 25a2 may be flat or curved surfaces.

[0106] Here, in a cross section along the radial direction of the axial fan 100, the straight line connecting the radial end point of the first region 25a1 on the inner circumferential side and the radial end point of the outer circumferential side is defined as locus L1, and the straight line connecting the radial end point of the second region 25a2 on the inner circumferential side and the radial end point of the outer circumferential side is defined as locus L2.

[0107] In addition, in a radial cross section of the axial fan 100, a line representing a plane perpendicular to the rotation axis RA is defined as a line FL. As shown in Figure 24, in a radial cross section of the axial fan 100, the angle between the line FL and the locus L1 of the first region 25a1 is defined as a first angle θ1. In addition, in a radial cross section of the axial fan 100, the angle between the line FL and the locus L2 of the second region 25a2 is defined as a second angle θ2.

[0108] The axial fan 100 according to the third embodiment is configured so that the first angle θ1 of the first region 25a1 is larger than the second angle θ2 of the second region 25a2. In other words, the axial fan 100 according to the third embodiment is configured so that the second angle θ2 of the second region 25a2 is smaller than the first angle θ1 of the first region 25a1.

[0109] As described above, in a radial cross section centered on the rotation axis RA, the outer peripheral portion 30 defines a first angle θ1, which is the angle between a locus L1 connecting the radially inner end point of the first region 25a1 to the radially outer end point of the first region 25a1 and a line FL representing a plane perpendicular to the rotation axis RA. Also, the outer peripheral portion 30 defines a second angle θ2, which is the angle between a locus L2 connecting the radially inner end point of the second region 25a2 to the radially outer end point of the second region 25a2 and the line FL representing a plane perpendicular to the rotation axis RA.

[0110] The outer circumferential portion 30 is formed such that, when the first angle θ1 and the second angle θ2 are compared, the first angle θ1 of the first region 25a1 is larger than the second angle θ2 of the second region 25a2. That is, the angle formed by a locus connecting the radially inner end point and the radially outer end point of each of the first region 25a1 and the second region 25a2 and a line representing a plane perpendicular to the fan axis direction is larger in the first region 25a1 than in the second region 25a2.

[0111] Effects of the Axial Fan 100 In a radial cross section centered on the rotation axis RA, the outer peripheral portion 30 of the axial fan 100 according to the third embodiment has a first region 25a1 that includes the outer edge 23 and a second region 25a2 that is continuous with the first region 25a1 on its inner circumferential side. The outer peripheral portion 30 is formed such that the first angle θ1 of the first region 25a1 is larger than the second angle θ2 of the second region 25a2. That is, the angle between a locus connecting the radially inner end point and the radially outer end point of each of the first region 25a1 and the second region 25a2 and a line representing a plane perpendicular to the fan axis direction is larger for the first region 25a1 than for the second region 25a2. In axial fan 100 according to the third embodiment, the outermost peripheral portions of blades 20 are curved up more steeply in the radial direction about rotation axis RA, which smooths the flow of fluid escaping from pressure surface 25 on the outer edge of the fan and further stabilizes tip vortices WL. As a result, tip vortices WL are not turbulent and are stable in axial fan 100, improving fan efficiency and achieving high efficiency.

[0112] Fourth Embodiment Figure 25 is a cross-sectional view of the blade 20 of an axial fan 100 according to a fourth embodiment. Figure 25 is a cross-sectional view of the blade 20 taken along line A-A in Figure 23, viewed in the direction of the arrows. Note that parts having the same configuration as those in the axial fan 100 of Figures 1 to 24 are given the same reference numerals, and their description will be omitted. The axial fan 100 according to the fourth embodiment further specifies the configuration of the negative pressure surface 26 of the outer circumferential portion 30.

[0113] In a radial cross section centered on the rotation axis RA, the axial fan 100 according to the fourth embodiment has a suction surface 26 that is recessed from the upstream side to the downstream side in the direction of fluid flow when the blades 20 rotate. More specifically, the axial fan 100 according to the fourth embodiment has an outer circumferential portion 30 having an outer circumferential suction surface 26 a. The suction surface 26 of the blade 20 includes the outer circumferential suction surface 26 a.

[0114] 25 , in a radial cross section of the axial fan 100, the cross section of the outer peripheral negative pressure surface 26a is formed into a shape that is concave from the upstream side to the downstream side in the direction of fluid flow by the axial fan 100. In other words, in a radial cross section of the axial fan 100, the cross section of the outer peripheral negative pressure surface 26a is curved in a shape that is convex from the upstream side to the downstream side in the direction of fluid flow by the axial fan 100. The outer peripheral negative pressure surface 26a is curved, for example, in an arc shape.

[0115] As shown in Fig. 25, the outer peripheral negative pressure surface 26a forms a surface facing inward of the blade 20. The outer peripheral negative pressure surface 26a forms a surface having a radial component centered on the rotation axis RA. The outer peripheral negative pressure surface 26a forms a surface on the inner surface side of the axial flow fan 100.

[0116] Outer peripheral negative pressure surface 26a is formed so as to curve from downstream to upstream in the direction of fluid flow generated by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23. Alternatively, outer peripheral negative pressure surface 26a is formed so as to curve up from downstream to upstream in the direction of fluid flow generated by axial flow fan 100, as it moves from the inner peripheral portion toward outer peripheral portion 23.

[0117] Due to the outer peripheral positive pressure surface 25a and the outer peripheral negative pressure surface 26a, the outer peripheral portion 30 of the blade 20 is formed so that the blade plate curves from downstream to upstream in the direction of fluid flow formed by the axial flow fan 100 as it moves from the inner peripheral portion toward the outer peripheral portion 23. Due to the outer peripheral positive pressure surface 25a and the outer peripheral negative pressure surface 26a, the outer peripheral portion 30 of the blade 20 is formed so that the blade plate curves up from downstream to upstream in the direction of fluid flow formed by the axial flow fan 100 as it moves from the inner peripheral portion toward the outer peripheral portion 23.

[0118] [Effects of the Axial Fan 100] In a radial cross section centered on the rotation axis RA, the outer peripheral portion 30 of the axial fan 100 according to the fourth embodiment has a suction surface 26 that is recessed from the upstream side toward the downstream side in the direction of fluid flow when the blades 20 rotate. That is, the shape of the suction surface 26 in the radial cross section is convex toward the downstream side. Because the blade tip vortex WL is a spiral, the suction surface 26 through which the blade tip vortex WL passes is configured in this manner, thereby smoothing the outer edge of the blade tip vortex WL. Therefore, the axial fan 100 according to the fourth embodiment can stably generate the blade tip vortex WL. The axial fan 100 stabilizes the blade tip vortex WL without turbulence, improving fan efficiency and achieving high efficiency.

[0119] Fifth Embodiment Figure 26 is a cross-sectional view of the blade 20 of an axial fan 100 according to a fifth embodiment. Figure 26 is a cross-sectional view of the blade 20 taken along line A-A in Figure 23, viewed in the direction of the arrows. Note that parts having the same configuration as those in the axial fan 100 of Figures 1 to 25 are given the same reference numerals, and their description will be omitted. The axial fan 100 according to the fifth embodiment further specifies the configuration of the outer edge 23 of the outer periphery 30.

[0120] Axial fan 100 according to embodiment 5 has outer periphery 30 with outer edge 23 that is rounded in a radial cross section taken about rotation axis RA. That is, axial fan 100 according to embodiment 5 has a rounded outer edge in a radial cross section. "Round" refers to a rounded, curved portion.

[0121] In the axial fan 100 according to the fifth embodiment, the corners between the outer surface 23 e and the negative pressure surface 26 and the corners between the outer surface 23 e and the outer peripheral positive pressure surface 25 a are rounded in a radial cross section of the axial fan 100. The outer surface 23 e is formed linearly in a radial cross section of the axial fan 100.

[0122] 27 is a cross-sectional view of a first modified example of the blade 20 of the axial fan 100 according to embodiment 5. In the blade 20 of the first modified example, the outer surface 23e is curved so as to have a rounded shape in a radial cross section of the axial fan 100. In the blade 20 of the first modified example, the outer edge 23 forms a continuous curved surface that forms a single round. In the blade 20 of the first modified example, the outer peripheral pressure surface 25a and the suction surface 26 are connected by a single round at the outer edge 23 in a radial cross section of the axial fan 100.

[0123] Effects of the Axial Fan 100 The outer peripheral portion 30 of the axial fan 100 according to the fifth embodiment has a rounded outer edge 23 in a radial cross section centered on the rotation axis RA. In the axial fan 100 according to the fifth embodiment, when the flow from the positive pressure surface 25 of the outer peripheral portion 30 flows toward the suction pressure surface 26, the outer peripheral portion 23 located between them is connected by a rounded portion, which allows the fluid flow to proceed smoothly and stabilizes the formation of the blade tip vortex WL. As a result, the axial fan 100 stabilizes the blade tip vortex WL without turbulence, thereby improving fan efficiency and achieving high efficiency.

[0124] Sixth Embodiment Figure 28 is a cross-sectional view of the blade 20 of an axial fan 100 according to a sixth embodiment. Figure 28 is a cross-sectional view of the blade 20 taken along line A-A in Figure 23, viewed in the direction of the arrows. Note that parts having the same configuration as those in the axial fan 100 of Figures 1 to 27 are given the same reference numerals, and their description will be omitted. The axial fan 100 according to the sixth embodiment further specifies the configuration of the outer edge 23 of the outer periphery 30.

[0125] In a radial cross section centered on the rotation axis RA, the axial fan 100 according to the sixth embodiment has an outer periphery 30, whose outer edge 23 is formed at an acute angle by the pressure surfaces 25 and suction surfaces 26 of the blades 20. That is, in the radial cross section of the axial fan 100 according to the sixth embodiment, the outer edge has an acute angle.

[0126] More specifically, blade 20 is formed so that negative pressure surface 26 and outer peripheral positive pressure surface 25 a form an acute angle in a radial cross section of axial fan 100. Blade 20 of axial fan 100 according to the sixth embodiment is formed so that negative pressure surface 26 and outer peripheral positive pressure surface 25 a form a triangle in a radial cross section of axial fan 100, with outer edge 23 forming the apex.

[0127] The outer peripheral portion 30 of the axial fan 100 according to the sixth embodiment is formed so that the blade thickness decreases from the inner periphery to the outer periphery in a radial cross section of the axial fan 100. The outer peripheral portion 30 of the axial fan 100 according to the sixth embodiment is formed so that the distance between the negative pressure surface 26 and the outer peripheral positive pressure surface 25 a in the axial direction of the rotation axis RA decreases from the inner periphery to the outer periphery in a radial cross section of the axial fan 100.

[0128] Effects of the Axial Fan 100 In the axial fan 100 according to the sixth embodiment, the outer peripheral portion 30 is formed at an acute angle by the pressure surfaces 25 and suction surfaces 26 of the blades 20 in a radial cross section centered on the rotation axis RA. If the outer peripheral portion 23 were thick, the fluid flow generated at the outer peripheral portion would come into contact with the blade wall surface, causing the fluid flow to become unstable. In the axial fan 100, the outer peripheral portion 23 is formed at an acute angle by the pressure surfaces 25 and suction surfaces 26 of the blades 20. This means that when the fluid flow separates from the pressure surfaces 25 at the outer peripheral portion 23, it is immediately drawn into the suction surface 26 without coming into contact with the blade wall surface, thereby stabilizing the blade tip vortex WL. As a result, the axial fan 100 achieves stable, undisturbed blade tip vortices WL, improving fan efficiency and achieving high efficiency.

[0129] Seventh Embodiment [Air Conditioner 70] In a seventh embodiment, the axial fan 100 or the like according to the first to sixth embodiments is applied as a blower 55 to the outdoor unit 50 of an air conditioner 70.

[0130] 29 is a schematic diagram of an air conditioner 70 according to embodiment 7. In the following explanation, the air conditioner 70 will be described as an apparatus using the axial fan 100, but the axial fan 100 is not limited to being used in the air conditioner 70. The axial fan 100 is used for refrigeration or air conditioning purposes, such as refrigerators, freezers, vending machines, air conditioners, refrigeration systems, and water heaters.

[0131] As shown in Figure 29, the air conditioner 70 includes a compressor 64 that compresses and discharges a refrigerant, a condenser 72 that condenses the refrigerant, an expansion valve 74, and an evaporator 73 that evaporates the refrigerant. The air conditioner 70 also includes a blower 55 (see Figure 31). The air conditioner 70 forms a refrigerant circuit 71 in which the compressor 64, condenser 72, expansion valve 74, and evaporator 73 are connected in this order by refrigerant piping.

[0132] The condenser 72 is provided with a condenser fan 72a that blows air for heat exchange to the condenser 72. The evaporator 73 is provided with an evaporator fan 73a that blows air for heat exchange to the evaporator 73. At least one of the condenser fan 72a and the evaporator fan 73a is configured with the axial fan 100 or the like according to any one of the above-described Embodiments 1 to 6. The air conditioner 70 may be configured to switch between heating operation and cooling operation by providing a flow switching device such as a four-way valve that switches the flow of refrigerant in the refrigerant circuit 71.

[0133] Fig. 30 is a perspective view of the outdoor unit 50 of an air conditioner 70 according to Embodiment 7, as viewed from the air outlet side. Fig. 31 is a diagram for explaining the configuration of the outdoor unit 50 from the top side. Fig. 32 is a diagram showing the state with the fan grill 54 removed from the outdoor unit 50. Fig. 33 is a diagram showing the internal configuration with the fan grill 54, front panel 51b, etc. removed from the outdoor unit 50.

[0134] 30 to 33, the outdoor unit main body 51, which is a casing, is configured as a housing having a pair of left and right side surfaces 51a and 51c, a front surface 51b, a rear surface 51d, a top surface 51e, and a bottom surface 51f. Openings (not shown) for drawing air from the outside are formed in the side surface 51a and the rear surface 51d.

[0135] On the front surface 51b, a front panel 52 is formed with an air outlet 53 as an opening for blowing air to the outside. Furthermore, the air outlet 53 is covered with a fan grill 54, which prevents contact between the axial flow fan 100 and objects outside the outdoor unit body 51, ensuring safety. The arrow AR in Figure 31 indicates the flow of air.

[0136] A blower 55 is housed inside the outdoor unit body 51. As shown in Figure 31 , the blower 55 has an axial fan 100 and a drive source 61. The drive source 61 is a fan motor, and provides driving force to the axial fan 100.

[0137] The axial flow fan 100 is connected to a rotary shaft 62 of a drive source 61 on the rear surface 51d side, and is rotationally driven by the drive source 61. The drive source 61 is attached to a motor support 69. The motor support 69 is disposed between the drive source 61 and the heat exchanger 68, and supports the drive source 61.

[0138] The interior of the outdoor unit body 51 is divided by a partition plate 51g, which serves as a wall, into an airflow chamber 56 in which an axial fan 100 is installed, and a machine chamber 57 in which a compressor 64 and other components are installed. A heat exchanger 68 that extends in a substantially L-shape in plan view is provided on the side surface 51a and the back surface 51d of the airflow chamber 56. The shape of the heat exchanger 68 is not limited to this shape, and may be formed, for example, in a straight line in plan view. The heat exchanger 68 functions as an evaporator 73 during heating operation and as a condenser 72 during cooling operation.

[0139] A bell mouth 63 is disposed radially outward of the axial fan 100 disposed in the blower chamber 56. The bell mouth 63 surrounds the outer periphery of the axial fan 100 and regulates the flow of gas formed by the axial fan 100 and the like. The bell mouth 63 is located outward of the outer periphery of the blades 20 and is provided in an annular shape along the rotation direction of the axial fan 100. Furthermore, a partition plate 51g is located on one side of the bell mouth 63, and part of a heat exchanger 68 is located on the other side.

[0140] The front end of the bell mouth 63 is connected to the front panel 52 of the outdoor unit 50 so as to surround the outer periphery of the air outlet 53. The bell mouth 63 may be configured integrally with the front panel 52, or may be provided as a separate unit that can be connected to the front panel 52. The bell mouth 63 configures a flow path between the suction side and the outlet side of the bell mouth 63 as an air passage near the air outlet 53. In other words, the air passage near the air outlet 53 is separated from other spaces in the air blower chamber 56 by the bell mouth 63.

[0141] The heat exchanger 68, which is provided on the suction side of the axial flow fan 100, includes a plurality of fins arranged in parallel with their plate-like surfaces, and heat transfer tubes that penetrate the fins in the arranging direction. Refrigerant circulating through the refrigerant circuit flows through the heat transfer tubes. In the heat exchanger 68 of this embodiment, the heat transfer tubes extend in an L shape from the side surface 51 a to the back surface 51 d of the outdoor unit body 51, and multiple stages of the heat transfer tubes snake through the fins.

[0142] The heat exchanger 68 is connected to the compressor 64 via piping 65 and the like, and is further connected to an indoor heat exchanger and an expansion valve 74 (not shown), etc., to form a refrigerant circuit 71 of the air conditioner 70. A circuit board box 66 is also disposed in the machine room 57, and a control board 67 provided in this circuit board box 66 controls the devices mounted in the outdoor unit.

[0143] The air conditioner 70 shown in Fig. 29 includes a blower 55, a motor support 69 that supports a drive source 61, a condenser 72 that condenses a refrigerant, and an evaporator 73 that evaporates the refrigerant. The blower 55 shown in Fig. 31 blows air to at least one of the condenser 72 and the evaporator 73.

[0144] [Effects of the Fan 55 and the Air Conditioner 70] The fan 55 includes an axial fan 100 according to any one of the first to sixth embodiments. The air conditioner 70 includes a fan 55 having an axial fan 100 according to any one of the first to sixth embodiments. Therefore, the fan 55 and the air conditioner 70 according to the seventh embodiment also achieve the same effects as the axial fan 100 according to any one of the first to sixth embodiments. Even when a turbulent fluid flow due to a structure such as a motor support flows into the axial fan 100, the axial fan 100 of the fan 55 and the air conditioner 70 reduces the circumferential velocity of the leading edge 21 of the blade 20, thereby reducing the blade tip vortex WL formed on the leading edge 21 side of the blade 20. Furthermore, the axial fan 100 of the fan 55 and the air conditioner 70 can direct the blade tip vortex WL, which expands from the leading edge 21 side toward the trailing edge 22 side, along the outer periphery 30. Therefore, in the blower 55 and air conditioner 70 equipped with the axial fan 100, the blade tip vortex WL on the negative pressure surface 26 of the axial fan 100 is stable and not disturbed, improving fan efficiency and achieving high efficiency.

[0145] The configurations shown in the above embodiments are merely examples, and may be combined with other known techniques, or parts of the configuration may be omitted or modified without departing from the spirit of the invention. For example, the inventions according to the third to sixth embodiments specify the configuration of the outer peripheral portion 30, but the inventions according to the third to sixth embodiments may also be applied to the configuration of the rear outer peripheral portion 40.

[0146] 10 Hub, 20 Blade, 20R Blade, 21 Leading edge portion, 22 Trailing edge portion, 23 Outer edge portion, 23a Reduced portion, 23b Rear outer edge portion, 23c Recessed portion, 23d Protruding portion, 23e Outer surface, 24 Inner edge portion, 25 Pressure surface, 25a Outer peripheral pressure surface, 25a1 First region, 25a2 Second region, 25b Rear outer peripheral pressure surface, 26 Negative pressure surface, 26a Outer peripheral negative pressure surface, 28 Blade surface, 30 Outer peripheral portion, 40 Rear outer peripheral portion, 50 Outdoor unit, 51 Outdoor unit body, 51a Side, 51b Front, 51c Side, 51d Rear, 51e Top, 51f Bottom, 51g Partition plate, 52 Front panel, 53 Air outlet, 54 Fan grill, 55 Blower, 56: blower chamber, 57: machine room, 61: drive source, 62: rotating shaft, 63: bell mouth, 64: compressor, 65: piping, 66: circuit board box, 67: control board, 68: heat exchanger, 69: motor support, 70: air conditioner, 71: refrigerant circuit, 72: condenser, 72a: condenser fan, 73: evaporator, 73a: evaporator fan, 74: expansion valve, 100: axial fan, 100L: axial fan, 100R: axial fan, 140: bending portion, 150: air conditioner, 150R: outdoor unit, 151: housing, 152: heat exchanger, 153: compressor, 154: motor, 155: motor support, 201: tip portion, 202: inflection portion, 203: rear end portion.

Claims

1. A hub that is driven to rotate and forms a rotation axis; a wing formed around the hub and having a leading edge, a trailing edge, an inner edge that is connected to the hub, and an outer edge that forms an outer edge between the leading edge and the trailing edge; Equipped with The wing is a reduced portion that forms a portion of the outer edge portion where the outer diameter of the blade is reduced in a leading edge portion side portion compared to a trailing edge portion that forms a maximum diameter of the blade; an outer peripheral portion that forms a pressure surface that curves from a downstream side to an upstream side in a flow direction of a fluid that flows when the blade rotates, as the outer peripheral portion moves from the inner peripheral portion to the outer peripheral portion in the contracting portion; having The outer periphery is An axial flow fan having a radial width centered on the rotation axis that is larger at a portion closer to the trailing edge than at a portion closer to the leading edge.

2. The outer periphery is The axial flow fan according to claim 1 , wherein the first and second fins are formed in a partial area of ​​the contracting portion in a circumferential direction around the rotation axis.

3. The outer periphery is The axial flow fan according to claim 1 , wherein the first and second fins are formed in the entire area of ​​the contraction portion in a circumferential direction around the rotation axis.

4. The wing is a tip portion which is a portion of the outer edge portion closest to the front edge portion; an inflection portion which is a portion of the outer edge portion that forms the outermost diameter of the blade and is located closest to the tip portion; having The reduction section is The inflection portion is formed in the entire region between the tip portion and the inflection portion in the circumferential direction around the rotation axis, The outer periphery is An axial flow fan according to any one of claims 1 to 3, wherein the radial width centered on the rotation axis is gradually increased from the tip end portion toward the trailing edge portion.

5. The wing is 4. An axial fan as described in claim 1, further comprising a rear outer peripheral portion which forms a positive pressure surface that curves from the downstream side to the upstream side in the flow direction of the fluid that flows when the blades rotate, on the trailing edge side of the reduction section, as it moves from the inner edge side toward the outer edge.

6. The outer periphery is In a radial cross section centered on the rotation axis, the first region includes the outer edge portion, and a second region is formed continuously with the first region on an inner peripheral side thereof, 4. The axial fan according to claim 1, wherein, in a radial cross section centered on the rotation axis, when a first angle is an angle between a locus connecting an end point on the inner side in the radial direction of the first region and an end point on the outer side in the radial direction and a straight line that represents a plane perpendicular to the rotation axis, and a second angle is an angle between a locus connecting an end point on the inner side in the radial direction of the second region and an end point on the outer side in the radial direction and a straight line that represents a plane perpendicular to the rotation axis, the first angle of the first region is larger than the second angle of the second region.

7. The outer periphery is An axial fan according to any one of claims 1 to 3, wherein in a radial cross section centered on the rotation axis, the negative pressure surface is concave from the upstream side to the downstream side in the flow direction of the fluid that flows when the blades rotate.

8. The outer periphery is 4. The axial flow fan according to claim 1, wherein the outer edge is formed in a rounded shape in a radial cross section taken about the rotation shaft.

9. The outer periphery is 4. An axial fan according to claim 1, wherein in a radial cross section centered on the rotation axis, the outer edge portion is formed at an acute angle by the positive pressure surface and the negative pressure surface of the blade.

10. An axial flow fan according to any one of claims 1 to 3; A drive source that applies a drive force to the axial flow fan; A blower equipped with

11. A blower according to claim 10; A motor support that supports the driving source; A condenser that condenses the refrigerant; an evaporator for evaporating the refrigerant; Equipped with The blower is An air conditioner that blows air to at least one of the condenser and the evaporator.