Axial flow fan and air conditioner comprising same

Abstract

An embodiment of the present invention relates to an axial flow fan having a plurality of blades, each comprising a hub connection unit, a leading edge, a trailing edge, and a tip, wherein the thickness of the leading edge, with respect to the direction in which a rotary shaft extends, decreases in a radial direction going outward, and the thickness of the trailing edge, with respect to the direction in which the rotary shaft extends, remains the same in the radial direction going outward.

Description

Axial fan and air conditioner including the same

[0001] The present invention relates to an axial fan and an air conditioner including the same.

[0002] An air conditioner is a device designed to maintain the air in a designated space in the most suitable condition according to its use or purpose. Generally, the air conditioner includes a compressor, a condenser, an expansion device, and an evaporator, and the designated space can be cooled or heated through the processes of compression, condensation, expansion, and evaporation of a refrigerant.

[0003] The above-mentioned condenser and evaporator are heat exchangers that exchange heat between the refrigerant and the outside air, and are provided in an indoor unit or an outdoor unit. The heat exchanger provided in the indoor unit is named the indoor heat exchanger, and the heat exchanger provided in the outdoor unit is named the outdoor heat exchanger.

[0004] An axial fan that blows air toward the heat exchanger may be provided on one side of the heat exchanger equipped in the outdoor unit.

[0005] The above-described axial fan includes a hub connected to the rotating shaft of a motor and a plurality of blades coupled to the outer side of the hub. When the axial fan rotates due to the driving of the motor, a pressure difference occurs between the front and rear surfaces of the plurality of blades, and this pressure difference generates a suction force that moves air.

[0006] Meanwhile, conventional axial fans have a problem in that the stress generated by centrifugal force reaches its maximum at the leading edge of the blade. To improve this, a structure can be applied in which the blade thickness is increased from the leading edge to the trailing edge along the radial direction of the fan; however, this results in a thicker trailing edge, which impairs flow performance and increases volume.

[0007] In other words, a structure is required that can improve fluidity performance by maintaining rigidity while reducing the blade thickness.

[0008] (Patent Document 1) Korean Published Patent No. 10-2015-0068665 (June 22, 2015)

[0009] The present invention is proposed to solve the above-mentioned problems.

[0010] An axial fan according to an embodiment of the present invention comprises a hub to which the rotational shaft of a motor is connected and a plurality of blades arranged in a circumferential direction on the outer surface of the hub.

[0011] Each of the plurality of blades comprises a hub connecting portion connected to the outer surface of the hub, a leading edge forming a front end with respect to the rotational direction of the blade, a trailing edge forming a rear end with respect to the rotational direction of the blade, and a tip connecting the leading edge and the trailing edge and forming the outermost end in the radial direction of the blade.

[0012] With respect to the direction in which the rotation axis extends, the thickness of the leading edge decreases as it extends radially outward, and the thickness of the trailing edge can be formed to be uniform as it extends radially outward.

[0013] With respect to the direction in which the above-mentioned rotational axis extends, the thickness of the above-mentioned leading edge may be maximum at the above-mentioned hub connection and minimum at the above-mentioned tip.

[0014] The thickness of the above-mentioned leading edge may gradually decrease from the hub connection to the tip based on the radial direction.

[0015] The line of change in thickness of the leading edge according to the radial distance from the hub connection part may extend in a non-linear form from the hub connection part to the tip.

[0016] The above-mentioned leading edge may have a profile in which the position of the inflection point is formed closer to the hub connection than to the tip with respect to the radial direction.

[0017] The profile of the above-mentioned leading edge may be backward between the hub connection and the inflection point with respect to the radial direction, and forward between the inflection point and the tip.

[0018] The profile of the above-mentioned leading edge may have a sweep angle that gradually increases as it progresses from the inflection point toward the tip.

[0019] With respect to the direction in which the above-mentioned rotation axis extends, the thickness of the rear edge may be formed to be smaller than the thickness of the front edge.

[0020] With respect to the direction in which the above-mentioned rotational axis extends, the thickness of the rear portion can be formed to be the same as that of the hub connection portion and the tip.

[0021] The thickness of the rear portion can be formed uniformly from the hub connection portion to the tip with respect to the radial direction.

[0022] The line of change in thickness of the rear edge according to the radial distance from the hub connection part can extend in a linear form from the hub connection part to the tip.

[0023] The blade may include a front portion of the blade comprising the leading edge, a part of the hub connecting portion, and a part of the tip, and a rear portion of the blade comprising the trailing edge, the remaining part of the hub connecting portion, and the remaining part of the tip.

[0024] The thickness of the rear portion of the blade adjacent to the hub connection may be formed to be smaller than the thickness of the front portion of the blade adjacent to the hub connection.

[0025] The thickness of the front portion of the blade may gradually decrease in the direction in which the rotation axis extends from the hub connection portion to the tip.

[0026] The rear portion of the blade may be formed with a thickness that is uniform in the direction in which the rotation axis extends from the hub connection portion to the tip.

[0027] The front portion of the blade may include a portion corresponding to the area between the leading edge and the maximum camber connecting line (L6) based on the circumferential direction.

[0028] The rear portion of the blade may include a portion corresponding to the area between the maximum camber connecting line (L6) and the rear edge (124) based on the circumferential direction.

[0029] The centerline of the cross-section of the above blade can be defined as the camber line (L2).

[0030] The line connecting the front and rear ends of the above camber line (L2) in a straight line can be defined as the cord line (L3).

[0031] The distance between the camber line (L2) and the cord line (L3) can be defined as the camber amount.

[0032] The maximum value of the above camber amount can be defined as the maximum camber amount (L4).

[0033] With respect to the direction parallel to the above code line (L3), the distance between the point having the maximum camber amount (L4) on the above camber line (L2) and the leading edge can be defined as the maximum camber position (L5).

[0034] The maximum camber connection line (L6) may be a line connecting countless points having the maximum camber amount (L4) on the camber line (L2) with respect to the radial direction of the blade.

[0035] The maximum camber connection line (L6) can be bent along a direction parallel to the rotational direction of the blade.

[0036] The maximum camber connection line (L6) can be positioned closer to the leading edge than to the trailing edge with respect to the circumferential direction.

[0037] According to the proposed invention, the following effects are achieved.

[0038] First, since a blade with a sharp tail is provided, air resistance is minimized, which has the advantage of reducing noise and increasing airflow.

[0039] Second, since the overall thickness of the blades can be reduced, there is an advantage in that the weight of the axial fan is reduced and manufacturing costs are lowered.

[0040] Third, since rigidity can be maintained while the blade thickness is reduced, there is an advantage of suppressing deformation and stress generated during fan rotation and improving flow performance.

[0041] FIG. 1 is a perspective view of an outdoor unit according to an embodiment of the present invention.

[0042] FIG. 2 is an exploded perspective view of an outdoor unit according to an embodiment of the present invention.

[0043] FIG. 3 is a cross-sectional view of an outdoor unit according to an embodiment of the present invention.

[0044] FIG. 4 is a perspective view showing an axial flow fan according to an embodiment of the present invention in the direction of the pressure plane.

[0045] FIG. 5 is a perspective view showing an axial fan according to an embodiment of the present invention in the direction of the suction surface.

[0046] FIG. 6 is a front view of an axial fan according to an embodiment of the present invention.

[0047] FIG. 7 is a rear view of an axial fan according to an embodiment of the present invention.

[0048] FIG. 8 is a side view of an axial fan according to an embodiment of the present invention.

[0049] FIG. 9 is a partial cross-sectional view of an axial fan according to an embodiment of the present invention.

[0050] FIG. 10 is a plan view showing a portion of the blade of an axial fan according to an embodiment of the present invention.

[0051] FIG. 11 is a side view illustrating the maximum camber position of an axial fan according to an embodiment of the present invention.

[0052] FIG. 12 is a drawing showing a thickness change section of a blade according to an embodiment of the present invention.

[0053] FIG. 13 is a graph showing the thickness change curve of the front part of a blade according to an embodiment of the present invention and the thickness change curve of the front part of a blade according to the prior art.

[0054] FIG. 14 is a graph showing the thickness change curve of the rear portion of a blade according to an embodiment of the present invention and the thickness change curve of the rear portion of a blade according to the prior art.

[0055] FIG. 15 is a graph showing the change in power consumption according to airflow for a conventional axial fan and the axial fan of the present invention.

[0056] Figure 16 is a graph showing the stress distribution generated on the blades under the same rotational speed conditions when a conventional axial fan is in operation.

[0057] FIG. 17 is a graph showing the stress distribution generated on the blades under the same rotational speed conditions when the axial flow fan of the present invention is in operation.

[0058] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. It should be noted that in assigning reference numerals to the components of the drawings, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0059] FIG. 1 is a perspective view of an outdoor unit according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of an outdoor unit according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of an outdoor unit according to an embodiment of the present invention.

[0060] Referring to FIGS. 1 to 3, the air conditioner according to an embodiment of the present invention may be a multi-air conditioning system capable of simultaneous cooling and heating that can air-condition the indoor space by operating in either a cooling or heating mode, or a heat pump type multi-air conditioning system capable of switching between cooling and heating modes to air-condition the indoor space.

[0061] The air conditioner according to the present embodiment may include one or more indoor units and one outdoor unit (10).

[0062] The above outdoor unit (10) may include a case that forms an exterior and accommodates a number of parts.

[0063] The case of the outdoor unit (10) may include a front panel (11) forming the front of the outdoor unit (10), a rear panel (12) spaced apart from the rear of the front panel (11) and forming the rear of the outdoor unit (10), an upper panel (13) provided on the upper side of the front panel (11) and the rear panel (12) and forming the upper surface of the outdoor unit (10), and left panels (14) and right panels (15) provided on both sides of the front panel (11) and the rear panel (12) and forming both sides of the outdoor unit (10).

[0064] An internal space is formed by being surrounded by the case of the above outdoor unit (10).

[0065] The outdoor unit (10) is equipped with an intake port (12A, 14A, 15A) through which outdoor air is drawn into the internal space, and an exhaust port (11A) through which outdoor air that has undergone heat exchange in the internal space is discharged.

[0066] The above intake ports (12A, 14A, 15A) may be formed in the rear panel (12), the left panel (14), and the right panel (15). The above discharge port (11A) may be formed in the front panel (11).

[0067] Outdoor air may be drawn in from the rear or side of the outdoor unit (10), then heat exchanged in the internal space and discharged to the front of the outdoor unit (10).

[0068] The above outdoor unit (10) may further include a service panel (16).

[0069] The service panel (16) may be formed rounded on one side of the front of the outdoor unit (10). The service panel (16) may include a service cover (16A).

[0070] Therefore, since the service panel (16) can open and close the front and side simultaneously with a single panel, a worker or manager can easily access the electrical room (60) described later through the service cover (16A).

[0071] The above outdoor unit (10) may further include a base (17) that forms the bottom surface of the above outdoor unit (10).

[0072] Various electrical components, including some components of the refrigeration cycle to be described later, may be placed on the upper surface of the base (17). The lower surface of the base (17) may come into contact with the ground to fix the outdoor unit (10) to the ground.

[0073] The above outdoor unit (10) may include a barrier (19) extending upward from the base (17).

[0074] The barrier (19) is a type of plate, and the lower end of the barrier (19) can be attached to the upper surface of the base (17). The upper end of the barrier (19) can be positioned at a predetermined distance from the upper surface panel (13). Additionally, the front end of the barrier (19) can be fixed to one side of the orifice (40) to be described later, and the rear end of the barrier (19) can be fixed to one side of the heat exchanger (24) to be described later.

[0075] The barrier (19) can divide the internal space of the outdoor unit (10) into a heat exchange room (50) and an electrical room (60). The heat exchange room (50) may be provided on the left side of the barrier (19), and the electrical room (60) may be located on the right side of the barrier (19).

[0076] The above heat exchange room (50) is a space in which an outdoor heat exchanger (24) and an axial fan (100), which will be described later, are arranged, and heat exchange occurs between the refrigerant passing through the outdoor heat exchanger (24) and the air flowing through the axial fan (100).

[0077] The above electrical room (60) is a space where an electrical unit (70), which is a type of control box, is located.

[0078] The above barrier (19) may include a rounded surface, and the surface of the barrier (19) may have a curvature corresponding to a component placed in the electric room (60).

[0079] The above outdoor unit (10) may be equipped with a compressor (21) for compressing refrigerant, an oil separator, a valve device, an outdoor heat exchanger (24), an outdoor expansion valve, a gas-liquid separator (25), and a plurality of refrigerant pipes (26).

[0080] The refrigerant compressed in the compressor (21) passes through the oil separator, and the oil is separated. The refrigerant from which the oil has been separated by the valve device can flow to either the outdoor heat exchanger (24) or the indoor heat exchanger of the indoor unit.

[0081] In the case of cooling operation of the above air conditioner, the refrigerant compressed by the valve device flows into the outdoor heat exchanger (24), the refrigerant condensed in the outdoor heat exchanger (24) is depressurized while passing through the outdoor expansion valve and then flows into the indoor unit, and the refrigerant evaporated in the indoor heat exchanger can be introduced back into the valve device.

[0082] In the case of heating operation of the above air conditioner, the refrigerant compressed by the valve device flows into the indoor heat exchanger of the indoor unit, and the refrigerant condensed in the indoor heat exchanger flows into the indoor unit after being depressurized while passing through the indoor expansion valve, and the refrigerant evaporated in the outdoor heat exchanger (24) can be introduced back into the valve device.

[0083] The refrigerant passing through the above valve device flows to the above gas-liquid separator (25), and after the liquid refrigerant is separated in the above gas-liquid separator (25), only the gaseous refrigerant flows into the above compressor (21) and can be operated according to the above refrigeration cycle.

[0084] The above outdoor heat exchanger (24) is configured to exchange heat between the refrigerant and the outside air, and acts as a condenser during cooling operation and as an evaporator during heating operation.

[0085] The outdoor heat exchanger (24) can be bent into an L shape. Accordingly, the outdoor heat exchanger (24) can be positioned adjacent to the rear panel (12) and the left panel (14), but it can also be positioned adjacent to the rear panel (12) and the right panel (14).

[0086] The above outdoor heat exchanger (24) may include a rear heat exchanger (24A) and a lateral heat exchanger (24B) that is bent and extended from the rear heat exchanger (24A).

[0087] The rear heat exchanger (24A) may be positioned corresponding to the rear panel (12), and the lateral heat exchanger (24B) may be positioned corresponding to the left panel (14).

[0088] The outdoor heat exchanger (24) includes an inlet surface into which outdoor air is introduced and a discharge surface into which heat-exchanged air is discharged. The inlet surface is a surface facing the rear panel (12) and the left panel (14) with respect to the outdoor heat exchanger (24), and the discharge surface is a surface facing the interior space of the outdoor unit (10).

[0089] The above outdoor unit (10) may be equipped with a motor (M), an axial fan (100), and a motor bracket (M / B).

[0090] The above motor (M) provides rotational force to the above axial fan (100).

[0091] The above axial fan (100) is connected to the rotating shaft of the motor (M) and circulates outdoor air as it rotates. The above axial fan (100) can draw in air in the axial direction and then discharge air in the radial direction. The above axial fan (100) can produce a high flow rate with low static pressure.

[0092] The motor bracket (M / B) is connected to the motor (M) and supports the motor (M) and the axial fan (100). The lower end of the motor bracket (M / B) may be connected to the upper surface of the base (17), and the upper end of the motor bracket (M / B) may be connected to the lower surface of the upper panel (13).

[0093] The motor (M) is connected to the front of the motor bracket (M / B), and the axial fan (100) is connected to the rotation axis of the motor (M), and the motor (M) and the axial fan (100) can be positioned to correspond to the discharge port (11A) of the front panel (11).

[0094] Accordingly, the discharge port (11A), the axial fan (100), the motor (M), the motor bracket (M / B), and the rear heat exchanger (24A) can be arranged sequentially from front to rear in the heat exchanger (50).

[0095] The above outdoor unit (10) may further include an orifice (40) that is provided between the discharge port (11A) and the axial fan (100) and connected to the front panel (11).

[0096] The orifice (40) may be located between the front panel (11) at the front and the axial fan (100) at the rear, and between the lateral heat exchanger (24B) on the left and the barrier (19) on the right.

[0097] Accordingly, the orifice (40) guides the outdoor air flowing from the axial fan (100) to the discharge port (11A) and prevents noise caused by the rotation of the axial fan (100) from being transmitted to the outside of the outdoor unit (10) through the side heat exchanger (24B).

[0098] FIG. 4 is a perspective view showing an axial fan according to an embodiment of the present invention in the direction of the pressure surface, FIG. 5 is a perspective view showing an axial fan according to an embodiment of the present invention in the direction of the suction surface, FIG. 6 is a front view of an axial fan according to an embodiment of the present invention, and FIG. 7 is a rear view of an axial fan according to an embodiment of the present invention.

[0099] Referring to FIGS. 4 to 7, an axial fan (100) according to an embodiment of the present invention may include a hub (110) to which the rotation axis of the motor (M) is connected, and a plurality of blades (120) disposed on the outer surface of the hub (110).

[0100] The above-mentioned rotating shaft can be extended forward from the motor (M) and coupled to the center of the hub (110).

[0101] The hub (110) may have a plate shape. One side of the hub (110) may be formed as a single curved surface or a flat surface. The rotation axis of the motor (M) may be coupled to the center of the hub (110).

[0102] In detail, the hub (110) may include a hub suction surface (111) forming an air intake side, a hub discharge surface (112) forming an air discharge side, and a hub outer surface (113) to which the plurality of blades (120) are connected.

[0103] In this embodiment, the hub suction surface (111) may be understood to form the "front portion" of the hub (110), the hub discharge surface (112) to form the "rear portion" of the hub (110), and the hub outer surface (113) to form the "side portion" of the hub (110).

[0104] Defines the direction.

[0105] Based on FIG. 5, the direction in which the shaft insertion part (115) extends from the hub suction surface (111) is defined as "forward".

[0106] Conversely, the direction from the hub suction surface (111) toward the hub discharge surface (112) is defined as "rear."

[0107] Based on Fig. 6, the direction extending radially with respect to the center of the axial fan (100) is defined as the "radial direction."

[0108] In addition, the direction in which the blade (120) is rotated is defined as the "rotation direction."

[0109] The hub suction surface (111) forms the suction side through which air blows and can form the front surface of the hub (110). The hub suction surface (111) can be formed in a polygonal shape. For example, the hub suction surface (111) can be formed in a polygonal shape corresponding to the number of blades (120).

[0110] In this embodiment, the blade (120) may be composed of three blades, for example. Accordingly, the hub suction surface (111) may be formed in a roughly triangular shape.

[0111] The above hub suction surface (111) can be formed as a single curved surface or a flat surface.

[0112] For example, one side of the hub suction surface (111) and one side of the blade (120) can be smoothly connected without a step. That is, the connecting portion of the hub suction surface (111) and the blade (120) may be aligned on the same line or have the same curvature.

[0113] The hub discharge surface (112) forms the air discharge side and can form the rear surface of the hub (110). The hub discharge surface (112) can be formed in a polygonal shape. For example, the hub discharge surface (112) can be formed in a polygonal shape corresponding to the number of blades (120). That is, the hub discharge surface (112) can be formed in a triangular shape.

[0114] The hub discharge surface (112) can be formed as a single curved surface or a flat surface.

[0115] For example, one side of the hub discharge surface (112) and one side of the blade (120) can be smoothly connected without a step. That is, the connecting portion of the hub discharge surface (112) and the blade (120) may be aligned on the same line or have the same curvature.

[0116] The hub outer surface (113) is connected to the blade (120) and can form a side or outer surface of the hub (110). The hub outer surface (113) may include a plurality of outer surface portions, each formed rounded with a certain curvature. The plurality of outer surface portions may be formed rounded with a set curvature.

[0117] For example, the outer surface of the hub (113) may include a plurality of outer surface portions corresponding to the number of blades (120).

[0118] In this embodiment, the blade (120) may be configured with three blades as an example. Accordingly, the outer surface of the hub (113) may include three outer surface portions.

[0119] The three outer surfaces mentioned above can be arranged such that the angle between adjacent outer surfaces is the same. That is, the hub (110) can be formed in the shape of a triangular plate overall.

[0120] The above hub (110) may include a shaft insertion part (115) into which the rotational shaft of the motor (M) is inserted.

[0121] The shaft insertion portion (115) may protrude a predetermined length from the hub suction surface (111). The shaft insertion portion (115) may protrude forward from the center of the hub suction surface (111). For example, the shaft insertion portion (115) may be formed in a cylindrical shape.

[0122] An insertion groove (115A) into which the rotational shaft of the motor (M) is inserted is formed inside the shaft insertion part (115).

[0123] The insertion groove (115A) may be formed by being recessed at the end of the shaft insertion part (115). For example, the insertion groove (115A) may be formed by being recessed backward from the center of the front end of the shaft insertion part (115).

[0124] The above blades (120) may be spaced apart and arranged in multiple numbers on the outer surface of the hub (110). The multiple blades (120) may be arranged in a circumferential direction on the outer surface of the hub (110).

[0125] In this embodiment, the blade (120) is composed of three blades, and the three blades may be spaced apart circumferentially from the outer surface of the hub (110).

[0126] The blade (120) may include a hub connecting part (121) connected to the outer surface of the hub (111) and a tip (122) forming the end of the blade (120).

[0127] Based on the radial direction of the blade (120), the hub connecting portion (121) forms the inner end of the blade (120), and the tip (122) can form the outer end of the blade (120).

[0128] The blade (120) may include a blade outer portion (130) extending from the tip (122) toward the hub (110) with a first curvature (gradient) and a blade inner portion (140) extending from the blade outer portion (130) toward the hub (110) with a second curvature (gradient).

[0129] The tip (122) is formed at the outer end of the outer part (130) of the blade, and the hub connection part (121) can be formed at the inner end of the inner part (140) of the blade.

[0130] An inflection point (135) may be defined between the outer part (130) of the blade and the inner part (140) of the blade.

[0131] For example, the inflection point (135) is a line separating the outer part (130) of the blade and the inner part (140) of the blade, and the inner part (140) of the blade may have a shape that bends somewhat sharply backward toward the hub (110) starting from the inflection point (135), that is, toward the hub discharge surface (112). Therefore, the inflection point (135) can be named a "bent part."

[0132] The inner part (140) of the blade extends from the outer part (130) of the blade toward the outer surface (113) of the hub (110). The inner part (140) of the blade may be formed to bend in one direction around the inflection point (135).

[0133] Accordingly, with respect to the direction perpendicular to the central axis of the hub (110), the direction in which the outer part of the blade (130) extends, i.e., the curvature or gradient of the outer part of the blade (130), may be formed differently from the direction in which the inner part of the blade (140) extends, i.e., the curvature or gradient of the inner part of the blade (140).

[0134] The outer part (130) of the blade may be named "outer wing part" or "first wing part," and the inner part (140) of the blade may be named "inner wing part" or "second wing part."

[0135] The blade (120) may include a leading edge (123) forming a front end in the rotational direction and a trailing edge (124) forming a rear end in the rotational direction.

[0136] The above leading edge (123) may form a side end corresponding to the part where the airflow begins to come into contact. The above leading edge (123) may be located at the inlet of the hub (110), that is, in the direction where the airflow flows in.

[0137] The above leading edge (123) can be understood as a part connecting the hub connecting part (121) and each tip of the tip (122).

[0138] The rear end (124) may form another side end corresponding to the part where the airflow is separated. The rear end (124) may be located at the outlet of the hub (110), that is, in the direction where the airflow is discharged.

[0139] The rear portion (124) can be understood as a part connecting the hub connecting portion (121) and each rear end of the tip (122).

[0140] In detail, the leading edge (123) includes a first leading edge (123A) provided on the outer part (130) of the blade and a second leading edge (123B) provided on the inner part (140) of the blade.

[0141] The above rear edge (124) includes a first rear edge (124A) provided on the outer part (130) of the blade and a second rear edge (124B) provided on the inner part (140) of the blade.

[0142] The first leading edge (123A) and the second leading edge (123B), and the first trailing edge (124Aa) and the second trailing edge (124B) can be distinguished based on the inflection point (135).

[0143] The second rear section (124B) extends in a direction corresponding to the extension direction of the first rear section (124A). That is, the second rear section (124B) can extend from the first rear section (124A) to the hub (110) without bending.

[0144] That is, at the point where the inflection point (135) and the rear edge (124) meet, the angle of bending from the outer part of the blade (130) to the inner part of the blade (140), i.e., the bending angle, can be understood to be close to 0 degrees.

[0145] Here, the point where the inflection point (135) and the rear edge (124) meet is defined as the second end (135B) of the inflection point (135).

[0146] On the other hand, the second leading edge (123B) is bent in a predetermined direction relative to the extension direction of the first leading edge (123A) and extends to the hub (110). In FIG. 4, the extension direction of the first leading edge (123A) is indicated by a virtual line (L1), and the extension direction of the second leading edge (123B) forms a set angle (θ1) with respect to the virtual line (L1).

[0147] That is, at the point where the inflection point (135) and the leading edge (123) meet, the angle of bending from the outer part of the blade (130) to the inner part of the blade (140), i.e., the bending angle, can be understood as θ1.

[0148] For example, the bending angle (θ1) can be formed in the range of about 50 to 70°.

[0149] Here, the point where the inflection point (135) and the leading edge (123) meet is defined as the first end (135A) of the inflection point (135).

[0150] In summary, the blade (120) does not bend at the point of the second end (135B) of the inflection section (135), but bends somewhat significantly at the point of the first end (135A) of the inflection section (135).

[0151] Ultimately, the inner part (140) of the blade can be formed such that it extends in a direction corresponding to the extension direction of the outer part (130) of the blade at the rear edge (124) side, while the angle of bending with respect to the extension direction of the outer part (130) of the blade becomes increasingly larger as it moves toward the front edge (123) side.

[0152] According to the configuration of the present invention, the blade (120) can maintain a large pitch angle, and accordingly, a sufficient amount of airflow can be secured due to the rotation of the blade.

[0153] Based on FIG. 4, the axial fan (100) can be rotated counterclockwise.

[0154] The blade (120) may include an intake surface (125) that defines the direction in which air blows and a pressure surface (126) that faces the direction in which air is discharged.

[0155] The suction surface (125) is understood as the surface through which air flows in while facing the front of the axial fan (100), and the pressure surface (126) is understood as the opposite side of the suction surface (125) while facing the rear of the axial fan (100).

[0156] The blade (120) may further include a corrugated portion. The corrugated portion may be formed on the rear edge (124) of the blade (120).

[0157] As shown in FIGS. 6 and 7, if the tips (122) of the plurality of blades (120) are extended in the circumferential direction, a virtual circle (C1) can be defined.

[0158] The radial distance from the center of the hub (110) to the virtual circle (C1) can be defined as the radius (R1) of the axial fan (100).

[0159] In addition, if the inflection point (135) of the plurality of blades (120) is extended in the circumferential direction, a virtual circle (C2) can be defined.

[0160] The radial distance from the center of the hub (110) to the virtual circle (C2) can be defined as the radius (R2) of the inflection point (135).

[0161] The ratio of the radius (R2) of the inflection part (135) to the radius (R1) of the axial fan (100) can be formed in the range of 0.36 to 0.46. For example, the ratio of the radius (R2) of the inflection part (135) to the radius (R1) of the axial fan (100) can be 0.41.

[0162] Additionally, if the outer surface of each hub (110) that is furthest away in the radial direction from the center of the hub (110) is extended in the circumferential direction, a virtual circle (C3) can be defined.

[0163] The radial distance from the center of the hub (110) to the virtual circle (C3) can be defined as the radius (R3) of the hub (110).

[0164] Compared to the overall size of the axial fan (100), the size of the hub (110) can be formed to be relatively small.

[0165] In detail, the outer surface of the hub (113) of the hub (110) forms one wall of the air passage through which air passes when the axial fan (100) rotates. The outer surface of the hub (113) is parallel to the direction of air flow and causes friction with the air, and due to this friction, a separation of the flow occurs, which can reduce the efficiency of the fan.

[0166] That is, if the size of the hub (110) is formed to be relatively large compared to the overall size of the axial fan (100), the friction area increases and consequently the width of the air passage becomes narrower, thereby degrading the performance of the axial fan.

[0167] Accordingly, in this embodiment, the ratio of the radius (R3) of the hub (110) to the radius (R1) of the axial fan (100) can be formed in the range of 0.175 to 0.233. For example, the ratio of the radius (R3) of the hub (110) to the radius (R1) of the axial fan (100) can be 0.198.

[0168] In this way, by configuring the size of the hub (110) to be relatively small, the magnitude of the frictional force generated between the flowing air and the hub (110) is reduced, thereby preventing the generation of vortices and improving fan efficiency.

[0169] In addition, as the size of the hub (110) is reduced, the weight of the axial fan (100) is reduced, and accordingly, the manufacturing cost is reduced.

[0170] In particular, the radius of curvature of the outer surface (113) of the hub (110) can be formed to be larger than the radius (R3) of the hub (110).

[0171] That is, the curvature of the outer surface of the hub (113) can be formed to be smaller than the curvature of the virtual circle (C3).

[0172] Additionally, the radius of curvature of the hub connection portion (121) of the blade (120) may be formed to be smaller than the radius of curvature of the outer surface of the hub (113).

[0173] That is, the curvature of the hub connection part (121) can be formed to be greater than the curvature of the outer surface of the hub (113).

[0174] Specifically, conventionally, when multiple blades are connected to a cylindrical hub, the curvature of the hub's outer surface causes a convex structure in the direction of the static pressure plane in the area of ​​the blade adjacent to the hub. Furthermore, a section where the convex camber direction is reversed (camber inversion phenomenon) inevitably occurs in the curved blade area connecting the blade and the hub, which causes a problem resulting in loss of fan performance.

[0175] However, in the present invention, the curvature of each outer surface of the hub connected to a plurality of blades is made gentle, and a hub having a polygonal shape equal to the number of blades is configured. Furthermore, by forming the curvature of the hub connection portion of each blade greater than the curvature of the outer surface of the hub, the camber (136) reversal phenomenon occurring in the blade section adjacent to the hub can be mitigated. Therefore, there is an effect of preventing the reduction of fan performance due to the camber reversal phenomenon.

[0176] FIG. 8 is a side view of an axial fan according to an embodiment of the present invention, and FIG. 9 is a partial cross-sectional view of an axial fan according to an embodiment of the present invention.

[0177] Referring to FIGS. 8 and 9, the axial fan (100) may include a reinforcing rib (150) connecting the hub (110) and the blade (120).

[0178] The reinforcing rib (150) functions to reinforce the strength of the axial fan (100) by connecting a part of the hub (110) and a part of the blade (120).

[0179] In order to reduce the weight of the above-mentioned axial fan (100) and improve the blowing performance, the size of the hub (110) can be reduced.

[0180] However, if the size of the hub (110) is reduced, the amount of deformation of the blade (120) due to the centrifugal force generated when the axial fan (100) rotates becomes excessive, and as a result, a large stress may occur on the joint surface between the blade (120) and the hub (110).

[0181] Therefore, in the present invention, by reinforcing the strength of the part where the hub (110) and the blade (120) are connected, loss of airflow and noise can be prevented.

[0182] The reinforcing rib (150) can be extended from the shaft insertion portion (115) of the hub (110) and connected to the suction surface (125) of the blade (120).

[0183] In detail, the reinforcing rib (150) may extend radially from the outer surface of the shaft insertion part (115) and come into contact with the suction surface (125) of the blade (120). The reinforcing rib (150) may be formed in a rounded rib shape that extends radially.

[0184] For example, the reinforcing rib (150) may extend radially from the outer surface of the shaft insertion part (115) and be connected to the suction surface (125) of the inner part of the blade (140). The reinforcing rib (150) may connect the center of the cross-section of the inner part of the blade (140) and the center of the rotation axis.

[0185] At this time, the reinforcing rib (150) does not come into contact with the outer part (130) of the blade. That is, the reinforcing rib (150) can be extended to connect the shaft insertion part (115) and the inner part (140) of the blade in a radial direction.

[0186] The above reinforcing rib (150) may have a width that extends in the front-rear direction.

[0187] That is, the reinforcing rib (150) may have a width in the direction in which the shaft insertion part (115) extends.

[0188] The width of the reinforcing rib (150) may gradually increase as it moves radially outward from the shaft insertion part (115), and may gradually decrease as it moves radially outward from a certain point.

[0189] That is, the width in the front-rear direction of the reinforcing rib (150) adjacent to the inner part (140) of the blade can be formed to be smaller than the width in the front-rear direction of the reinforcing rib (150) adjacent to the shaft insertion part (115).

[0190] The reinforcing rib (150) may be positioned at the center of the inner part (140) of the blade. The reinforcing rib (150) may be connected to the center of the rotational cross-section of the inner part (140) of the blade.

[0191] The reinforcing rib (150) may be formed to be inclined in the direction in which the shaft insertion part (115) extends as it moves radially outward from the shaft insertion part (115).

[0192] For example, the reinforcing rib (150) may be extended forward in a rounded manner from the outer surface of the shaft insertion part (115). In this case, the outer end (150A) of the reinforcing rib (150) may protrude further forward than the front end of the shaft insertion part (115).

[0193] When a virtual line (L2) extending radially from the outer end (150A) of the reinforcing rib (150) is defined, the extension direction of the shear portion (150B) of the reinforcing rib (150) forms a set angle (θ2) with respect to the virtual line (L2).

[0194] The above-mentioned setting angle (θ2) may be formed to be the same as or similar to the above-mentioned bending angle (θ1). For example, the above-mentioned setting angle (θ2) may be formed in the range of 60 to 70°.

[0195] According to one embodiment, the reinforcing rib (150) may include a first portion (151) that extends radially from the shaft insertion portion (115) and is connected to the hub (110), and a second portion (152) that extends further radially from the end of the first portion (151) and is connected to the inner portion (140) of the blade.

[0196] The first portion (151) may be extended radially from the shaft insertion portion (115) and connected to the hub suction surface (111) of the hub (110). As the first portion (151) extends radially outward, the front portion may be formed to be inclined forward or rounded.

[0197] The radial length of the first part (151) can be formed to be longer than the radial length of the second part (152).

[0198] And the width of the first part (151) in the front-rear direction can gradually increase as it moves radially outward. That is, as the width of the first part (151) in the front-rear direction gradually increases as it moves radially outward, it can firmly support the space between the shaft insertion part (115) and the hub (110).

[0199] The second part (152) may be extended further radially from the end of the first part (151) and connected to the suction surface (125) of the inner part (140) of the blade. As the second part (152) extends radially outward, the front end may be formed to be inclined or rounded toward the front. At this time, the angle of inclination of the end of the second part (152) may be formed to be greater than the angle of inclination of the end of the first part (151).

[0200] The width of the second part (152) may gradually decrease as it moves outward in the radial direction. That is, by decreasing the width of the second part (152) in the front-rear direction as it moves outward in the radial direction, the cross-sectional area in contact with the inner part (140) of the blade can be increased while minimizing the size and weight of the reinforcing rib (150).

[0201] According to the configuration of the present invention, it is possible to suppress deformation and stress occurring during the rotation of the fan without making the size of the reinforcing rib (150) excessive. In addition, by minimizing the size of the reinforcing rib (150), it is possible to minimize air resistance and reduce weight.

[0202] The above reinforcing ribs (150) may be provided in multiple numbers. The reinforcing ribs (150) may be formed in a number corresponding to the number of blades (120).

[0203] In this embodiment, the blade (120) may be composed of three, for example. Accordingly, the reinforcing rib (150) may be composed of three.

[0204] The plurality of reinforcing ribs (150) may be spaced apart in the circumferential direction on the outer surface of the shaft insertion part (115). For example, the plurality of reinforcing ribs (150) may be spaced apart at equal intervals in the circumferential direction on the outer surface of the shaft insertion part (115).

[0205] The three reinforcing ribs mentioned above may be arranged such that the angle between adjacent reinforcing ribs is the same. That is, the plurality of reinforcing ribs (150) may have a tripod structure overall.

[0206] If the outer ends of the above-mentioned plurality of reinforcing ribs (150) are extended in the circumferential direction, a virtual circle (C4) can be defined.

[0207] The radial distance from the center of the hub (110) to the virtual circle (C4) can be defined as the radius (R4) of the reinforcing rib (150).

[0208] The ratio of the radius (R4) of the reinforcing rib (150) to the radius (R1) of the axial fan (100) can be formed in the range of 0.2 to 0.4. For example, the ratio of the radius (R4) of the reinforcing rib (150) to the radius (R1) of the axial fan (100) can be 0.25.

[0209] That is, the radial distance (R4) from the center of the hub (110) to the outer end of the reinforcing rib (150) can be formed in the range of 20% to 40% of the radial distance (R1) from the center of the hub (110) to the outer end of the blade (120).

[0210] In this embodiment, the radius (R4) of the reinforcing rib (150) may be formed to be larger than the radius (R3) of the hub (110) and smaller than the radius (R2) of the inflection part (135).

[0211] That is, the radial distance (R4) from the center of the hub (110) to the outer end of the reinforcing rib (150) can be formed to be greater than the radial distance (R3) from the center of the hub (110) to the outer end of the hub (110) and smaller than the radial distance (R2) from the center of the hub (110) to the inflection point (135).

[0212] The plurality of reinforcing ribs (150) can be arranged radially inward with respect to each bend (135) of the blade (120).

[0213] FIG. 10 is a plan view showing a portion of the blade of an axial fan according to an embodiment of the present invention, FIG. 11 is a side view for explaining the maximum camber position of an axial fan according to an embodiment of the present invention, and FIG. 12 is a drawing showing a section of the blade thickness change according to an embodiment of the present invention.

[0214] FIG. 13 is a graph showing the thickness change curve of the front part of a blade according to an embodiment of the present invention and the thickness change curve of the front part of a blade according to the prior art, and FIG. 14 is a graph showing the thickness change curve of the rear part of a blade according to an embodiment of the present invention and the thickness change curve of the rear part of a blade according to the prior art.

[0215] Referring to FIGS. 10 to 14, the blade (120) includes a hub connecting portion (121) connected to the outer surface of the hub (110), a leading edge portion (123) forming a leading edge based on the rotational direction of the blade (120), a trailing edge portion (124) forming a trailing edge based on the rotational direction of the blade (120), and a tip (122) connecting the leading edge portion (123) and the trailing edge portion (124) and forming the outermost end in the radial direction of the blade (120).

[0216] Additionally, the blade (120) may include an inner blade portion (140) forming the hub connection portion (121) and an outer blade portion (130) forming the tip (122).

[0217] The blade (120) may have a concave shape in which the profile of the leading edge (123) is bent along a direction parallel to the rotational direction (DR) of the blade (120).

[0218] Specifically, the profile of the leading edge (123) may have a composite curve shape that is backward between the hub connecting part (121) and the inflection point (a) and forward between the inflection point (a) and the tip (122) based on the radial direction.

[0219] That is, the inflection point (a) can be defined as a boundary point or turning point where the profile of the leading edge (123) changes from backward to forward.

[0220] The above leading edge (123) may have a profile in which the radial position of the inflection point (a) is formed closer to the hub connecting part (121) than to the tip (122) based on the radial direction. That is, the radial distance from the hub connecting part (121) to the inflection point (a) may be formed to be smaller than the radial distance from the inflection point (a) to the tip (122).

[0221] For example, the blade (120) may be set such that the radial distance from the hub connection (121) to the inflection point (a) has a distance ratio greater than 0.2 and less than 0.5 with respect to the radial distance from the hub connection (121) to the tip (122).

[0222] Setting the distance ratio greater than 0.2 in this way is intended to prevent stress from concentrating on the joint side of the hub connection part (121) of the blade (120) and the hub (110), because if the position of the inflection point (a) is formed very close to the hub connection part (121), the leading edge (123) of the blade (120) becomes excessively bent in the rotational direction.

[0223] This is because such stress concentration can cause the blade (120) to break during high-speed rotation of the axial fan, and by maintaining the distance ratio greater than 0.2, the breakage of the blade (120) can be prevented.

[0224] In addition, the reason for setting the above distance ratio to be smaller than 0.5 is that if the position of the inflection point (a) at the leading edge (123) of the blade (120) is located beyond half of the radial effective width of the blade (120), almost no noise reduction effect occurs.

[0225] Meanwhile, the axial fan (100) according to the embodiment of the present invention can further reduce noise generation by optimizing the sweep angle (θa) of the leading edge (123) at the radial outer side of the inflection point (a).

[0226] For example, the sweep angle (θa) of the leading edge (123) can be defined as the angle at which the leading edge (123) extends in a rotational direction with respect to the radial direction from the inflection point (a).

[0227] At this time, the axial fan (100) can be set so that the sweep angle (θa) of the leading edge (123) gradually increases as it moves outward in the radial direction, and reaches a maximum at the tip (122). For example, the maximum sweep angle (θa) at the leading edge (123) can be set to be between 43 and 65 degrees.

[0228] The reason for setting the maximum sweep angle (θa) to 43 degrees or more is that if the maximum sweep angle (θa) is a value smaller than 43 degrees, for example 30 degrees, the noise reduction effect relative to the same generated air volume may actually decrease further.

[0229] In addition, the maximum sweep angle (θa) is set to 65 degrees or less because if the maximum sweep angle (θa) exceeds 65 degrees, the leading edge (123) becomes excessively bent in the rotational direction, which may cause breakage due to stress concentration during high-speed rotation, and the weight of the blade (120) may increase, thereby increasing power consumption.

[0230] Accordingly, in order to prevent the deterioration of power consumption due to increased rotational load, the thickness of the leading edge (123) of the blade (120) can be gradually reduced as it progresses radially outward with respect to a direction parallel to the rotation axis of the hub (110). That is, the thickness of the leading edge (123) of the blade (120) can be maximum at the hub connection (121) and minimum at the tip (122).

[0231] In particular, as illustrated in FIG. 13, in order to prevent the blade (120) from breaking due to stress concentration near the inflection point (a), the line of change in the thickness of the leading edge (123) of the blade (120) according to the radial distance can be configured to extend in a non-linear form.

[0232] The thickness change line of the leading edge (123) of the blade (120) according to an embodiment of the present invention may be composed of a composite straight line (V) formed by combining a plurality of straight lines having different rates of change as they proceed from the hub connecting part (121) to the tip (122).

[0233] Specifically, the plurality of straight lines may include a first straight line (V1) extending at a first rate of change from the hub connection part (121) to a first radial position where the distance ratio is 0.4, a second straight line (V2) extending at a second rate of change from the first position to a second radial position where the distance ratio is 0.5, and a third straight line (V3) extending at a third rate of change from the second position to the tip (122).

[0234] At this time, the second rate of change may be formed to be larger than the first rate of change and the third rate of change, and the third rate of change may be formed to be larger than the first rate of change.

[0235] In this way, by maintaining the rate of change (first rate of change) of the inner region of the forward-facing inflection point smaller than the rate of change (third rate of change) of the outer region of the backward-facing inflection point, the rigidity of the tip (122) side can be further reinforced, and the thickness of the outer region of the inflection point, which has a wider effective area, can be reduced by a larger rate of change, thereby preventing an increase in weight and worsening of power consumption of the blade (120).

[0236] In addition, the rate of change of thickness of the leading edge (123) near the inflection point (second rate of change) is configured to be a straight line that smoothly connects the first position and the second position, thereby having the effect of further reducing the stress concentration phenomenon near the inflection point where the direction changes from backward to forward.

[0237] Referring to FIG. 11, the blade (120) according to an embodiment of the present invention may have a camber line (L2), a cord line (L3), a maximum camber amount (L4), and a maximum camber position (P5), etc.

[0238] The above camber line (L2) or mean camber line may refer to the centerline on the cross-section of the blade (120).

[0239] That is, the camber line (L2) may mean a line connecting the center between the suction surface (125) and the pressure surface (126) of the blade (120).

[0240] The above chord line (L3) may mean a line that connects the front end (P1) of the camber line (L2) and the rear end (P2) of the camber line (L2) in a straight line.

[0241] That is, the above code line (L3) may mean a straight line connecting a point on the front edge (123) and a point on the rear edge (124).

[0242] The distance between the above camber line (L2) and the above cord line (L3) can be defined as the camber amount, and the maximum value of the above camber amount can be defined as the maximum camber amount (L4).

[0243] With respect to the direction parallel to the above code line (L3), the distance between the point (P3) having the maximum camber amount (L4) on the above camber line (L2) and the leading edge (213) can be defined as the maximum camber position (L5).

[0244] Additionally, the blade (120) has numerous points (P4, P5, P6, etc.) having the maximum camber amount (L4) on the camber line (L2) with respect to the radial direction, and a maximum camber connecting line (L6) connecting the numerous points (P4, P5, P6, etc.) can be defined.

[0245] For example, the maximum camber connection line (L6) can connect a point (P4) of the hub connection part (121), a point (P5) of the tip (122), and a point (P6) between the hub connection part (121) and the tip (122).

[0246] The maximum camber connecting line (L6) extends from the hub connecting part (121) of the blade (120) to the tip (122) and may have a concave shape by being bent along a direction parallel to the rotational direction of the blade (120).

[0247] At this time, the maximum camber connecting line (L6) may be positioned closer to the leading edge (123) than to the trailing edge (124) of the blade (120).

[0248] That is, the circumferential distance between the maximum camber connecting line (L6) and the leading edge (123) can be formed to be smaller than the circumferential distance between the maximum camber connecting line (L6) and the trailing edge (124).

[0249] According to one embodiment, the blade (120) may be divided into a blade front portion (137) corresponding to the area between the leading edge (123) and the maximum camber connecting line (L6) based on the circumferential direction of the axial fan (100), and a blade rear portion (138) corresponding to the area between the maximum camber connecting line (L6) and the trailing edge (124).

[0250] That is, the front part (137) of the blade may include the leading edge (123), and the rear part (138) of the blade may include the trailing edge (124).

[0251] And the front part of the blade (137) may include a part of the hub connection part (121) and a part of the tip (122), and the rear part of the blade (138) may include the remaining part of the hub connection part (121) and the remaining part of the tip (122).

[0252] As illustrated in FIG. 13, the thickness of the blade front portion (137) can gradually decrease in the direction in which the rotation axis extends from the hub connection portion (121) to the tip (122).

[0253] For example, the thickness of the leading edge (123) of the blade (120) may gradually decrease from the hub connecting part (121) to the tip (122) with respect to the radial direction.

[0254] That is, the line of change in thickness of the blade front portion (137) according to the radial distance from the hub connection portion (121) can be extended in a non-linear form from the hub connection portion (121) to the tip (122).

[0255] On the other hand, as illustrated in FIG. 14, the rear portion of the blade (138) can have its thickness reduced (formed) equally in the direction in which the rotation axis extends from the hub connection portion (121) to the tip (122).

[0256] For example, the thickness of the rear edge (124) of the blade (120) can be reduced (formed) equally from the hub connection (121) to the tip (122) with respect to the radial direction.

[0257] That is, the line of change in thickness of the rear portion of the blade (138) according to the radial distance from the hub connecting portion (121) can be extended in a linear form from the hub connecting portion (121) to the tip (122).

[0258] In other words, the thickness (T2) of the rear portion of the blade (138) adjacent to the hub connection portion (121) and the thickness of the rear portion of the blade (138) adjacent to the tip (122) may be the same.

[0259] And the thickness of the rear portion (138) of the blade adjacent to the hub connection portion (121) may be smaller than the thickness of the front portion (137) of the blade adjacent to the hub connection portion (121).

[0260] Meanwhile, in the case of a conventional blade, the thickness (T1) of the rear portion (138) of the blade adjacent to the hub connection portion (121) is formed to be the same as the thickness of the front portion (137) of the blade adjacent to the hub connection portion (121). However, in this case, the thickness of the rear portion (138) of the blade adjacent to the hub (110) becomes relatively thick, which has the problem of impeding flow performance and increasing volume.

[0261] Accordingly, in the present invention, the thickness (T2) of the rear portion (138) of the blade adjacent to the hub connection portion (121) is made relatively small, thereby reducing the thickness of the blade while maintaining rigidity and improving fluidity performance.

[0262] According to this configuration, the axial fan (100) according to the present invention can provide a blade (120) having a sharp rear end.

[0263] In addition, reducing the thickness up to the rear end of the blade based on the maximum camber connection line connecting the maximum camber positions of the blade has the effect of reducing losses due to air resistance and securing rigidity.

[0264] In addition, as the rear end shape of the blade becomes thinner, the volume of the axial fan is reduced, resulting in the effect of reducing material costs.

[0265] FIG. 15 is a graph showing the change in power consumption according to airflow for a conventional axial fan and the axial fan of the present invention.

[0266] Referring to Fig. 15, the horizontal axis of the graph represents the airflow value generated by the operation of the axial fan, and the vertical axis of the graph represents the power consumption value generated by the operation of the axial fan.

[0267] As the above airflow value increases, the above power consumption value tends to increase.

[0268] In particular, it can be seen that the increase in power consumption is smaller when the axial fan according to the present invention is adopted compared to when a conventional axial fan is adopted.

[0269] Specifically, it can be seen that when the axial fan according to the present invention is adopted compared to when a conventional axial fan is adopted, the power consumption value is reduced by up to 3.5%.

[0270] Therefore, when driving an axial fan equipped with a sharp rear end according to the present embodiment, power consumption can be significantly reduced compared to conventional methods.

[0271] FIG. 16 is a graph showing the stress distribution generated on the blades under the same rotational speed conditions when a conventional axial fan is in operation, and FIG. 17 is a graph showing the stress distribution generated on the blades under the same rotational speed conditions when the axial fan of the present invention is in operation.

[0272] FIG. 16 shows the stress distribution measured on the blade when a conventional axial fan is in operation. That is, in the axial fan of FIG. 16, the thickness of the leading edge (123) and trailing edge (124) of the blade (120) can be gradually reduced from the hub connection (121) to the tip (122).

[0273] FIG. 17 shows the stress distribution measured on the blade when the axial fan of the present invention is in operation. That is, in the axial fan of FIG. 17, the thickness of the leading edge (123) of the blade (120) gradually decreases from the hub connection (121) to the tip (122), while the thickness of the trailing edge (123) of the blade (120) can be equally decreased (formed) from the hub connection (121) to the tip (122).

[0274] Referring to FIGS. 16 and 17, it can be seen that the area of ​​high stress generated under the same rotational speed condition of approximately 1000 rpm is similar in both the conventional and the present invention.

[0275] In other words, it has been experimentally confirmed that in the case of the present invention, where the sharp rear end of the blade is applied, strength can be effectively maintained even under high rotational speed operating conditions.

Claims

1. A hub to which the rotating shaft of the motor is connected; and It includes a plurality of blades arranged circumferentially on the outer surface of the above hub, and Each of the above plurality of blades is, A hub connecting part connected to the outer surface of the above hub; A leading edge that forms a shear based on the rotational direction of the blade; A trailing edge forming a rear end based on the rotational direction of the blade; and It includes a tip that connects the leading edge and the trailing edge and forms the outermost end in the radial direction of the blade, With respect to the direction in which the above-mentioned rotation axis extends, the thickness of the above-mentioned leading edge gradually decreases as it moves radially outward, and An axial flow fan in which the thickness of the rear edge is formed uniformly as it extends radially outward, based on the direction in which the above-mentioned rotational axis is extended.

2. In Paragraph 1, An axial fan in which the thickness of the leading edge is maximum at the hub connection and minimum at the tip, based on the direction in which the rotational axis extends.

3. In Paragraph 1, The thickness of the above-mentioned leading edge is an axial fan that gradually decreases from the hub connection to the tip based on the radial direction.

4. In Paragraph 1, The line of change in thickness of the leading edge according to the radial distance from the hub connection is an axial fan extending in a non-linear form from the hub connection to the tip.

5. In Paragraph 1, The above-mentioned leading edge is an axial fan having a profile in which the position of the inflection point is formed closer to the hub connection than to the tip with respect to the radial direction.

6. In Paragraph 5, The profile of the above-mentioned leading edge is a axial fan that is backward between the hub connection and the inflection point with respect to the radial direction, and forward between the inflection point and the tip.

7. In Paragraph 6, The profile of the above-mentioned leading edge is an axial fan in which the sweep angle gradually increases as it progresses from the inflection point toward the tip.

8. In Paragraph 1, An axial fan in which the thickness of the rear edge is formed to be smaller than the thickness of the leading edge based on the direction in which the rotation axis is extended.

9. In Paragraph 1, An axial fan in which the thickness of the rear portion is formed equally at the hub connection portion and the tip with respect to the direction in which the rotational axis extends.

10. In Paragraph 1, The thickness of the rear portion is formed uniformly from the hub connection portion to the tip with respect to the radial direction, forming an axial flow fan.

11. In Paragraph 1, The line of change in thickness of the rear edge according to the radial distance from the hub connection is an axial fan extending in a linear form from the hub connection to the tip.

12. In Paragraph 1, The above blade is, A blade front portion comprising the aforementioned leading edge portion, a part of the aforementioned hub connecting portion, and a part of the aforementioned tip; and An axial fan comprising a blade rear portion including the above-mentioned rear edge, the remaining part of the above-mentioned hub connection portion, and the remaining part of the above-mentioned tip.

13. In Paragraph 12, An axial fan in which the thickness of the rear portion of the blade adjacent to the hub connection is formed to be smaller than the thickness of the front portion of the blade adjacent to the hub connection.

14. In Paragraph 12, The above-described blade front portion is an axial fan in which the thickness in the direction in which the rotation axis extends gradually decreases from the hub connection portion to the tip.

15. In Paragraph 12, An axial fan in which the rear portion of the blade is formed with a uniform thickness in the direction in which the rotation axis extends from the hub connection portion to the tip.

16. In Paragraph 12, The front portion of the blade includes a portion corresponding to the area between the leading edge and the maximum camber connecting line (L6) based on the circumferential direction, The rear portion of the blade above is an axial fan that includes a portion corresponding to the area between the maximum camber connecting line (L6) and the rear edge (124) based on the circumferential direction.

17. In Paragraph 16, The centerline of the cross-section of the above blade is defined as the camber line (L2), and A straight line connecting the front and rear ends of the above camber line (L2) is defined as a cord line (L3), and The distance between the above camber line (L2) and the above cord line (L3) is defined as the camber amount, and The maximum value of the above camber amount is defined as the maximum camber amount (L4), and When the distance between the point having the maximum camber amount (L4) on the camber line (L2) and the leading edge is defined as the maximum camber position (L5) with respect to the direction parallel to the above code line (L3), The above maximum camber connecting line (L6) is an axial fan that is a line connecting countless points having the maximum camber amount (L4) on the camber line (L2) with respect to the radial direction of the blade.

18. In Paragraph 17, The above maximum camber connection line (L6) is an axial fan that bends along a direction parallel to the rotational direction of the blade.

19. In Paragraph 17, The above maximum camber connecting line (L6) is an axial fan positioned closer to the leading edge than to the trailing edge with respect to the circumferential direction.

20. An air conditioner comprising an axial fan as described in any one of claims 1 to 19.

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